diff --git a/SimPEG/Mesh/TreeMesh.py b/SimPEG/Mesh/TreeMesh.py
index c9dfde32..040a300d 100644
--- a/SimPEG/Mesh/TreeMesh.py
+++ b/SimPEG/Mesh/TreeMesh.py
@@ -160,10 +160,12 @@ class TreeMesh(BaseTensorMesh, InnerProducts):
 
     @property
     def fill(self):
+        """How filled is the mesh compared to a TensorMesh? As a fraction: [0,1]."""
         return float(self.nC)/((2**self.maxLevel)**self.dim)
 
     @property
     def maxLevel(self):
+        """The maximum level used, which may be less than `levels`."""
         l = 0
         for cell in self._cells:
             p = self._pointer(cell)
@@ -307,7 +309,6 @@ class TreeMesh(BaseTensorMesh, InnerProducts):
         self.number()
         return len(self._hangingEz)
 
-
     @property
     def ntN(self):
         self.number()