diff --git a/Libraries/Core/Helpers/ItemHelper.cs b/Libraries/Core/Helpers/ItemHelper.cs
index e36da7b7..cc2cd4ec 100644
--- a/Libraries/Core/Helpers/ItemHelper.cs
+++ b/Libraries/Core/Helpers/ItemHelper.cs
@@ -339,7 +339,7 @@ public class ItemHelper(
     // @param string tpl Item to check base classes of
     // @param string[] baseClassTpls base classes to check for
     // @returns true if any supplied base classes match
-    public bool IsOfBaseclasses(string tpl, List<string> baseClassTpls)
+    public bool IsOfBaseclasses(string tpl, ICollection<string> baseClassTpls)
     {
         return _itemBaseClassService.ItemHasBaseClass(tpl, baseClassTpls);
     }
diff --git a/Libraries/Core/Services/ItemBaseClassService.cs b/Libraries/Core/Services/ItemBaseClassService.cs
index b1bf7e97..32955dcd 100644
--- a/Libraries/Core/Services/ItemBaseClassService.cs
+++ b/Libraries/Core/Services/ItemBaseClassService.cs
@@ -62,7 +62,7 @@ public class ItemBaseClassService(
      * @param baseClass base class to check for
      * @returns true if item inherits from base class passed in
      */
-    public bool ItemHasBaseClass(string itemTpl, List<string> baseClasses)
+    public bool ItemHasBaseClass(string itemTpl, ICollection<string> baseClasses)
     {
         if (!_cacheGenerated)
         {