diff --git a/cads_adaptors/adaptors/roocs/operators.py b/cads_adaptors/adaptors/roocs/operators.py
index 82186613..126d9490 100644
--- a/cads_adaptors/adaptors/roocs/operators.py
+++ b/cads_adaptors/adaptors/roocs/operators.py
@@ -110,7 +110,8 @@ def level(self):
             levels = [levels]
 
         levels = [
-            list(re.finditer(r"[\d]*[.][\d]+|[\d]+", level))[0] for level in levels
+            list(re.finditer(r"[\d]*[.][\d]+|[\d]+", level))[0].string
+            for level in levels
         ]
 
         for i, level in enumerate(levels):