diff --git a/csiborgtools/fits/halo.py b/csiborgtools/fits/halo.py
index 8a6765b..77b83bf 100644
--- a/csiborgtools/fits/halo.py
+++ b/csiborgtools/fits/halo.py
@@ -431,7 +431,8 @@ class Clump:
     @property
     def center_mass(self):
         """
-        Clump center of mass.
+        Clump center of mass. Note that this is already in a frame centered at
+        the clump's potential minimum.
 
         Returns
         -------