diff --git a/src/WarrenCowleyParameters/__init__.py b/src/WarrenCowleyParameters/__init__.py
index f6cf7da..47b5d35 100644
--- a/src/WarrenCowleyParameters/__init__.py
+++ b/src/WarrenCowleyParameters/__init__.py
@@ -205,7 +205,8 @@ def _get_labels_and_values(self, unique_types, wc_for_shells, shell_index):
         labels, values = [], []
         idx = range(len(unique_types))
 
-        for i, j in itertools.combinations_with_replacement(idx, 2):
+        # for i, j in itertools.combinations_with_replacement(idx, 2):
+        for i, j in itertools.combinations(idx, 2):
             namei = self.get_type_name(unique_types[i])
             namej = self.get_type_name(unique_types[j])
             labels.append(f"{namei}-{namej}")