diff --git a/ras_stac/ras1d/utils/classes.py b/ras_stac/ras1d/utils/classes.py
index ea78d8c..b4126bc 100644
--- a/ras_stac/ras1d/utils/classes.py
+++ b/ras_stac/ras1d/utils/classes.py
@@ -86,7 +86,7 @@ def endswith(self, suffix: str) -> bool:
 
     @property
     def is_ras_prj(self) -> bool:
-        if not self.endswith(".prj"):
+        if not self.lower().endswith(".prj"):
             return False
         if self.file_str is None:
             self.download_asset_str()