diff --git a/combo/apps/maps/models.py b/combo/apps/maps/models.py
index 600ada55..26af1f7d 100644
--- a/combo/apps/maps/models.py
+++ b/combo/apps/maps/models.py
@@ -429,7 +429,7 @@ class MapLayerOptions(models.Model):
             validators.MinValueValidator(0),
             validators.MaxValueValidator(1)],
         null=True,
-        help_text=_('Float value between 0 and 1'),
+        help_text=_('Float value between 0 (transparent) and 1 (opaque)'),
     )
 
     class Meta: