diff --git a/README.md b/README.md
index 64001a19..f6d49bb5 100644
--- a/README.md
+++ b/README.md
@@ -146,6 +146,32 @@ class Order extends BaseOrder implements SetonoSyliusGiftCardPluginOrderInterfac
     }
 }
 ```
+
+**Extend `OrderItemUnit`**
+
+```php
+<?php
+
+# src/Entity/Order/OrderItemUnit.php
+
+declare(strict_types=1);
+
+namespace App\Entity\Order;
+
+use Doctrine\ORM\Mapping as ORM;
+use Setono\SyliusGiftCardPlugin\Model\OrderItemUnitInterface as SetonoSyliusGiftCardOrderItemUnitInterface;
+use Setono\SyliusGiftCardPlugin\Model\OrderItemUnitTrait as SetonoSyliusGiftCardOrderItemUnitTrait;
+use Sylius\Component\Core\Model\OrderItemUnit as BaseOrderItemUnit;
+
+/**
+ * @ORM\Entity
+ * @ORM\Table(name="sylius_order_item_unit")
+ */
+class OrderItemUnit extends BaseOrderItemUnit implements SetonoSyliusGiftCardOrderItemUnitInterface
+{
+    use SetonoSyliusGiftCardOrderItemUnitTrait;
+}
+```
     
 **Extend `OrderRepository`:**
 
@@ -205,6 +231,9 @@ sylius_order:
             classes:
                 model: App\Entity\Order\Order
                 repository: App\Doctrine\ORM\OrderRepository
+        order_item_unit:
+            classes:
+                model: App\Entity\Order\OrderItemUnit
                 
 sylius_product:
     resources:
diff --git a/spec/Model/GiftCardSpec.php b/spec/Model/GiftCardSpec.php
index 48b8485b..f4f4e935 100644
--- a/spec/Model/GiftCardSpec.php
+++ b/spec/Model/GiftCardSpec.php
@@ -7,9 +7,9 @@
 use PhpSpec\ObjectBehavior;
 use Setono\SyliusGiftCardPlugin\Model\GiftCard;
 use Setono\SyliusGiftCardPlugin\Model\GiftCardInterface;
+use Setono\SyliusGiftCardPlugin\Model\OrderItemUnitInterface;
 use Sylius\Component\Core\Model\ChannelInterface;
 use Sylius\Component\Core\Model\OrderInterface;
-use Sylius\Component\Core\Model\OrderItemUnitInterface;
 use Sylius\Component\Resource\Model\ResourceInterface;
 
 class GiftCardSpec extends ObjectBehavior
diff --git a/spec/Operator/OrderGiftCardOperatorSpec.php b/spec/Operator/OrderGiftCardOperatorSpec.php
index fc25d80e..793067a3 100644
--- a/spec/Operator/OrderGiftCardOperatorSpec.php
+++ b/spec/Operator/OrderGiftCardOperatorSpec.php
@@ -11,12 +11,12 @@
 use Setono\SyliusGiftCardPlugin\Factory\GiftCardFactoryInterface;
 use Setono\SyliusGiftCardPlugin\Model\GiftCardInterface;
 use Setono\SyliusGiftCardPlugin\Model\OrderInterface;
+use Setono\SyliusGiftCardPlugin\Model\OrderItemUnitInterface;
 use Setono\SyliusGiftCardPlugin\Model\ProductInterface;
 use Setono\SyliusGiftCardPlugin\Operator\OrderGiftCardOperator;
 use Setono\SyliusGiftCardPlugin\Operator\OrderGiftCardOperatorInterface;
 use Setono\SyliusGiftCardPlugin\Repository\GiftCardRepositoryInterface;
 use Sylius\Component\Core\Model\OrderItemInterface;
-use Sylius\Component\Core\Model\OrderItemUnitInterface;
 
 class OrderGiftCardOperatorSpec extends ObjectBehavior
 {
diff --git a/src/Factory/GiftCardFactory.php b/src/Factory/GiftCardFactory.php
index bb217b82..aff2201a 100644
--- a/src/Factory/GiftCardFactory.php
+++ b/src/Factory/GiftCardFactory.php
@@ -6,10 +6,10 @@
 
 use Setono\SyliusGiftCardPlugin\Generator\GiftCardCodeGeneratorInterface;
 use Setono\SyliusGiftCardPlugin\Model\GiftCardInterface;
+use Setono\SyliusGiftCardPlugin\Model\OrderItemUnitInterface;
 use Sylius\Component\Core\Model\ChannelInterface;
 use Sylius\Component\Core\Model\CustomerInterface;
 use Sylius\Component\Core\Model\OrderInterface;
-use Sylius\Component\Core\Model\OrderItemUnitInterface;
 use Sylius\Component\Resource\Factory\FactoryInterface;
 use Webmozart\Assert\Assert;
 
diff --git a/src/Factory/GiftCardFactoryInterface.php b/src/Factory/GiftCardFactoryInterface.php
index 431555b1..00c1c59c 100644
--- a/src/Factory/GiftCardFactoryInterface.php
+++ b/src/Factory/GiftCardFactoryInterface.php
@@ -5,8 +5,8 @@
 namespace Setono\SyliusGiftCardPlugin\Factory;
 
 use Setono\SyliusGiftCardPlugin\Model\GiftCardInterface;
+use Setono\SyliusGiftCardPlugin\Model\OrderItemUnitInterface;
 use Sylius\Component\Core\Model\ChannelInterface;
-use Sylius\Component\Core\Model\OrderItemUnitInterface;
 use Sylius\Component\Resource\Factory\FactoryInterface;
 
 interface GiftCardFactoryInterface extends FactoryInterface
diff --git a/src/Model/GiftCard.php b/src/Model/GiftCard.php
index ffb2cfaf..cf0923e7 100644
--- a/src/Model/GiftCard.php
+++ b/src/Model/GiftCard.php
@@ -10,7 +10,6 @@
 use Sylius\Component\Core\Model\ChannelInterface;
 use Sylius\Component\Core\Model\CustomerInterface;
 use Sylius\Component\Core\Model\OrderInterface;
-use Sylius\Component\Core\Model\OrderItemUnitInterface;
 use Sylius\Component\Resource\Model\TimestampableTrait;
 use Sylius\Component\Resource\Model\ToggleableTrait;
 
@@ -84,6 +83,7 @@ public function getOrderItemUnit(): ?OrderItemUnitInterface
     public function setOrderItemUnit(OrderItemUnitInterface $orderItem): void
     {
         $this->orderItemUnit = $orderItem;
+        $orderItem->setGiftCard($this);
     }
 
     public function getOrder(): ?OrderInterface
diff --git a/src/Model/GiftCardInterface.php b/src/Model/GiftCardInterface.php
index 2e85bd5d..14472e5f 100644
--- a/src/Model/GiftCardInterface.php
+++ b/src/Model/GiftCardInterface.php
@@ -8,7 +8,6 @@
 use Sylius\Component\Core\Model\ChannelInterface;
 use Sylius\Component\Core\Model\CustomerInterface;
 use Sylius\Component\Core\Model\OrderInterface;
-use Sylius\Component\Core\Model\OrderItemUnitInterface;
 use Sylius\Component\Resource\Model\CodeAwareInterface;
 use Sylius\Component\Resource\Model\ResourceInterface;
 use Sylius\Component\Resource\Model\TimestampableInterface;
diff --git a/src/Model/OrderItemUnitInterface.php b/src/Model/OrderItemUnitInterface.php
new file mode 100644
index 00000000..3c0a0075
--- /dev/null
+++ b/src/Model/OrderItemUnitInterface.php
@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Setono\SyliusGiftCardPlugin\Model;
+
+use Sylius\Component\Core\Model\OrderItemUnitInterface as BaseOrderItemUnitInterface;
+
+interface OrderItemUnitInterface extends BaseOrderItemUnitInterface
+{
+    public function getGiftCard(): ?GiftCardInterface;
+
+    public function setGiftCard(GiftCardInterface $giftCard): void;
+}
diff --git a/src/Model/OrderItemUnitTrait.php b/src/Model/OrderItemUnitTrait.php
new file mode 100644
index 00000000..3c1d916a
--- /dev/null
+++ b/src/Model/OrderItemUnitTrait.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Setono\SyliusGiftCardPlugin\Model;
+
+use Doctrine\ORM\Mapping as ORM;
+
+trait OrderItemUnitTrait
+{
+    /**
+     * @var GiftCardInterface|null
+     *
+     * @ORM\OneToOne (targetEntity="Setono\SyliusGiftCardPlugin\Model\GiftCardInterface", mappedBy="orderItemUnit")
+     */
+    protected $giftCard;
+
+    public function getGiftCard(): ?GiftCardInterface
+    {
+        return $this->giftCard;
+    }
+
+    public function setGiftCard(GiftCardInterface $giftCard): void
+    {
+        $this->giftCard = $giftCard;
+    }
+}
diff --git a/src/Model/OrderTrait.php b/src/Model/OrderTrait.php
index 4b7794e1..2e747245 100644
--- a/src/Model/OrderTrait.php
+++ b/src/Model/OrderTrait.php
@@ -4,10 +4,15 @@
 
 namespace Setono\SyliusGiftCardPlugin\Model;
 
+use function assert;
 use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\Common\Collections\Collection;
 use Doctrine\ORM\Mapping as ORM;
+use Sylius\Component\Core\Model\Order;
 
+/**
+ * @mixin Order
+ */
 trait OrderTrait
 {
     /**
@@ -38,6 +43,8 @@ public function hasGiftCards(): bool
 
     public function addGiftCard(GiftCardInterface $giftCard): void
     {
+        assert($this instanceof OrderInterface);
+
         if (!$this->hasGiftCard($giftCard)) {
             $this->giftCards->add($giftCard);
             $giftCard->addAppliedOrder($this);
@@ -46,6 +53,8 @@ public function addGiftCard(GiftCardInterface $giftCard): void
 
     public function removeGiftCard(GiftCardInterface $giftCard): void
     {
+        assert($this instanceof OrderInterface);
+
         if ($this->hasGiftCard($giftCard)) {
             $this->giftCards->removeElement($giftCard);
             $giftCard->removeAppliedOrder($this);
diff --git a/src/Operator/OrderGiftCardOperator.php b/src/Operator/OrderGiftCardOperator.php
index 8a2705d2..8cba7efa 100644
--- a/src/Operator/OrderGiftCardOperator.php
+++ b/src/Operator/OrderGiftCardOperator.php
@@ -9,11 +9,11 @@
 use Setono\SyliusGiftCardPlugin\EmailManager\GiftCardEmailManagerInterface;
 use Setono\SyliusGiftCardPlugin\Factory\GiftCardFactoryInterface;
 use Setono\SyliusGiftCardPlugin\Model\GiftCardInterface;
+use Setono\SyliusGiftCardPlugin\Model\OrderItemUnitInterface;
 use Setono\SyliusGiftCardPlugin\Model\ProductInterface;
 use Setono\SyliusGiftCardPlugin\Repository\GiftCardRepositoryInterface;
 use Sylius\Component\Core\Model\OrderInterface;
 use Sylius\Component\Core\Model\OrderItemInterface;
-use Sylius\Component\Core\Model\OrderItemUnitInterface;
 use Webmozart\Assert\Assert;
 
 /**
diff --git a/src/Resources/config/app/fixtures.yaml b/src/Resources/config/app/fixtures.yaml
index e7ba7415..db52d513 100644
--- a/src/Resources/config/app/fixtures.yaml
+++ b/src/Resources/config/app/fixtures.yaml
@@ -24,18 +24,17 @@ sylius_fixtures:
                                 code: '1USD'
                                 channel: 'FASHION_WEB'
                                 currency: 'USD'
-                                initial_amount: 2.00
                                 amount: 1.00
                             gift_card_two_usd:
                                 code: '2USD'
                                 channel: 'FASHION_WEB'
-                                initial_amount: 2.00
+                                amount: 2.00
                 
                 setono_gift_card_configuration:
                     options:
                         custom:
                             default_configuration:
                                 code: 'default_configuration'
-                                background_image: '@SetonoSyliusGiftCardPlugin/Resources/fixtures/default_background.jpg'
+                                background_image: '@SetonoSyliusGiftCardPlugin/Resources/fixtures/default_background.png'
                                 enabled: true
                                 default: true
diff --git a/src/Resources/config/doctrine/model/GiftCard.orm.xml b/src/Resources/config/doctrine/model/GiftCard.orm.xml
index 79acf90b..23ce53c5 100644
--- a/src/Resources/config/doctrine/model/GiftCard.orm.xml
+++ b/src/Resources/config/doctrine/model/GiftCard.orm.xml
@@ -1,6 +1,5 @@
 <doctrine-mapping xmlns:gedmo="http://gediminasm.org/schemas/orm/doctrine-extensions-mapping"
                   xmlns="http://doctrine-project.org/schemas/orm/doctrine-mapping">
-
     <mapped-superclass name="Setono\SyliusGiftCardPlugin\Model\GiftCard" table="setono_sylius_gift_card__gift_card">
         <id name="id" column="id" type="integer">
             <generator strategy="AUTO"/>
@@ -8,8 +7,8 @@
 
         <field name="code" unique="true"/>
         <field name="enabled" type="boolean"/>
-        <field name="initialAmount" type="integer"/>
         <field name="amount" type="integer"/>
+        <field name="initialAmount" type="integer"/>
         <field name="currencyCode" length="3"/>
 
         <field name="createdAt" column="created_at" type="datetime">
@@ -28,12 +27,13 @@
             <join-column name="channel_id" referenced-column-name="id" nullable="false"/>
         </many-to-one>
 
-        <many-to-one field="orderItemUnit" target-entity="Sylius\Component\Order\Model\OrderItemUnitInterface">
+        <!-- Refers to the order item unit where this gift card was bought -->
+        <one-to-one field="orderItemUnit" target-entity="Sylius\Component\Order\Model\OrderItemUnitInterface" inversed-by="giftCard">
             <join-column name="order_item_unit_id" referenced-column-name="id" on-delete="SET NULL"/>
-        </many-to-one>
+        </one-to-one>
 
+        <!-- A list of orders where this gift card was applied / used -->
         <many-to-many field="appliedOrders" target-entity="Sylius\Component\Order\Model\OrderInterface"
                       mapped-by="giftCards"/>
     </mapped-superclass>
-
 </doctrine-mapping>
diff --git a/src/Resources/fixtures/default_background.jpg b/src/Resources/fixtures/default_background.jpg
deleted file mode 100644
index 06841c61..00000000
Binary files a/src/Resources/fixtures/default_background.jpg and /dev/null differ
diff --git a/src/Resources/fixtures/default_background.png b/src/Resources/fixtures/default_background.png
new file mode 100644
index 00000000..0c3a1fb0
Binary files /dev/null and b/src/Resources/fixtures/default_background.png differ
diff --git a/src/Resources/views/Shop/GiftCard/pdf.html.twig b/src/Resources/views/Shop/GiftCard/pdf.html.twig
index 6cdcf3ee..67edf041 100644
--- a/src/Resources/views/Shop/GiftCard/pdf.html.twig
+++ b/src/Resources/views/Shop/GiftCard/pdf.html.twig
@@ -4,25 +4,25 @@
 {% endif %}
 
 <html lang="{{ sylius_base_locale }}">
-<head>
-    <title>Gift card: {{ giftCard.code }}</title>
-    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
-    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/normalize.css@8.0.1/normalize.min.css">
-    <style>
-        body {
-            font-family: sans-serif;
-            font-size: 3rem;
-            background: transparent url("{{ path }}") no-repeat left bottom;
-            background-size: 100px;
-        }
+    <head>
+        <title>Gift card: {{ giftCard.code }}</title>
+        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
+        <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/normalize.css@8.0.1/normalize.min.css">
+        <style>
+            body {
+                font-family: sans-serif;
+                font-size: 3rem;
+                background: transparent url("{{ path }}") no-repeat left bottom;
+                background-size: 100px;
+            }
 
-        img {
-            display: block;
-        }
-    </style>
-</head>
-<body>
-{{- giftCard.code -}}<br>
-{{- giftCard.amount|sylius_format_money(giftCard.currencyCode, sylius_base_locale) -}}
-</body>
+            img {
+                display: block;
+            }
+        </style>
+    </head>
+    <body>
+        {{- giftCard.code -}}<br>
+        {{- giftCard.amount|sylius_format_money(giftCard.currencyCode, sylius_base_locale) -}}
+    </body>
 </html>
diff --git a/tests/Application/Model/OrderItemUnit.php b/tests/Application/Model/OrderItemUnit.php
new file mode 100644
index 00000000..9bac153e
--- /dev/null
+++ b/tests/Application/Model/OrderItemUnit.php
@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Setono\SyliusGiftCardPlugin\Application\Model;
+
+use Doctrine\ORM\Mapping as ORM;
+use Setono\SyliusGiftCardPlugin\Model\OrderItemUnitInterface as SetonoSyliusGiftCardOrderItemUnitInterface;
+use Setono\SyliusGiftCardPlugin\Model\OrderItemUnitTrait as SetonoSyliusGiftCardOrderItemUnitTrait;
+use Sylius\Component\Core\Model\OrderItemUnit as BaseOrderItemUnit;
+
+/**
+ * @ORM\Entity
+ * @ORM\Table(name="sylius_order_item_unit")
+ */
+class OrderItemUnit extends BaseOrderItemUnit implements SetonoSyliusGiftCardOrderItemUnitInterface
+{
+    use SetonoSyliusGiftCardOrderItemUnitTrait;
+}
diff --git a/tests/Application/config/packages/_sylius.yaml b/tests/Application/config/packages/_sylius.yaml
index 41580228..bfd52b85 100644
--- a/tests/Application/config/packages/_sylius.yaml
+++ b/tests/Application/config/packages/_sylius.yaml
@@ -1,9 +1,7 @@
 imports:
     - { resource: "@SyliusCoreBundle/Resources/config/app/config.yml" }
-
     - { resource: "@SyliusAdminBundle/Resources/config/app/config.yml" }
     - { resource: "@SyliusAdminApiBundle/Resources/config/app/config.yml" }
-
     - { resource: "@SyliusShopBundle/Resources/config/app/config.yml" }
 
 parameters:
@@ -25,6 +23,9 @@ sylius_order:
             classes:
                 model: Tests\Setono\SyliusGiftCardPlugin\Application\Model\Order
                 repository: Tests\Setono\SyliusGiftCardPlugin\Application\Doctrine\ORM\OrderRepository
+        order_item_unit:
+            classes:
+                model: Tests\Setono\SyliusGiftCardPlugin\Application\Model\OrderItemUnit
                 
 sylius_product:
     resources:
diff --git a/tests/Application/templates/bundles/SyliusAdminBundle/Order/Show/Summary/_item.html.twig b/tests/Application/templates/bundles/SyliusAdminBundle/Order/Show/Summary/_item.html.twig
new file mode 100644
index 00000000..878d5b9f
--- /dev/null
+++ b/tests/Application/templates/bundles/SyliusAdminBundle/Order/Show/Summary/_item.html.twig
@@ -0,0 +1,58 @@
+{# @var \Sylius\Component\Core\Model\OrderItemInterface item #}
+{% import "@SyliusAdmin/Common/Macro/money.html.twig" as money %}
+
+{% set orderPromotionAdjustment = constant('Sylius\\Component\\Core\\Model\\AdjustmentInterface::ORDER_PROMOTION_ADJUSTMENT') %}
+{% set unitPromotionAdjustment = constant('Sylius\\Component\\Core\\Model\\AdjustmentInterface::ORDER_UNIT_PROMOTION_ADJUSTMENT') %}
+{% set shippingAdjustment = constant('Sylius\\Component\\Core\\Model\\AdjustmentInterface::SHIPPING_ADJUSTMENT') %}
+{% set taxAdjustment = constant('Sylius\\Component\\Core\\Model\\AdjustmentInterface::TAX_ADJUSTMENT') %}
+
+{% set variant = item.variant %}
+{% set product = variant.product %}
+
+{% set aggregatedUnitPromotionAdjustments = item.getAdjustmentsTotalRecursively(unitPromotionAdjustment) + item.getAdjustmentsTotalRecursively(orderPromotionAdjustment) %}
+{% set subtotal = (item.unitPrice * item.quantity) + aggregatedUnitPromotionAdjustments %}
+
+{% set taxIncluded = sylius_admin_order_unit_tax_included(item) %}
+{% set taxExcluded = sylius_admin_order_unit_tax_excluded(item) %}
+
+<tr>
+    <td class="single line">
+        {% include '@SyliusAdmin/Product/_info.html.twig' %}
+        {# @var \Setono\SyliusGiftCardPlugin\Model\OrderItemUnitInterface itemUnit #}
+        {% for itemUnit in item.units %}
+            {% set giftCard = itemUnit.giftCard %}
+            {% if giftCard is not null %}
+                {{ giftCard.code }}
+            {% endif %}
+        {% endfor %}
+    </td>
+    <td class="right aligned unit-price">
+        {{ money.format(item.unitPrice, order.currencyCode) }}
+    </td>
+    <td class="right aligned unit-discount">
+        {{ money.format(item.units.first.adjustmentsTotal(unitPromotionAdjustment), order.currencyCode) }}
+    </td>
+    <td class="right aligned unit-order-discount">
+        <span style="font-style: italic;">~ {{ money.format(item.units.first.adjustmentsTotal(orderPromotionAdjustment), order.currencyCode) }}</span>
+    </td>
+    <td class="right aligned discounted-unit-price">
+        {{ money.format(item.fullDiscountedUnitPrice, order.currencyCode) }}
+    </td>
+    <td class="right aligned quantity">
+        {{ item.quantity }}
+    </td>
+    <td class="right aligned subtotal">
+        {{ money.format(subtotal, order.currencyCode) }}
+    </td>
+    <td class="right aligned tax">
+        <div class="tax-excluded">{{ money.format(taxExcluded, order.currencyCode) }}</div>
+        <div class="tax-disabled">
+            <div class="tax-included"> {{ money.format(taxIncluded, order.currencyCode) }}
+            </div>
+            <small>({{ 'sylius.ui.included_in_price'|trans }})</small>
+        </div>
+    </td>
+    <td class="right aligned total">
+        {{ money.format(item.total, order.currencyCode) }}
+    </td>
+</tr>