diff --git a/conversion_utils/jos_msds_and_properties.py b/conversion_utils/jos_msds_and_properties.py
index 8ec8c13..604dd06 100644
--- a/conversion_utils/jos_msds_and_properties.py
+++ b/conversion_utils/jos_msds_and_properties.py
@@ -247,7 +247,11 @@ class UD:
         return self._features_string()
 
     def to_full_string(self):
-        return "UposTag=" + self.pos + "|" + self._features_string()
+        features = self._features_string()
+        if features:
+            return "UposTag=" + self.pos + "|" + features
+        else:
+            return "UposTag=" + self.pos
 
     def _features_string(self):
         return "|".join([f"{feature}={value}" for feature, value in self._sort_features(self.features_map)])