diff --git a/pcore/segment.py b/pcore/segment.py
index ee362c4e7b2d3752d51aee7ff2466018a26e4cbd..2ca9f2eab8de8918a040deab2fc94fc9a4088fcf 100644
--- a/pcore/segment.py
+++ b/pcore/segment.py
@@ -250,8 +250,11 @@ class Tiler:
 
         Parameters:
         ----------
-        full: Numpy array image
-        slices: tuple of slices indicating the range
+        full: (zstacks, max_size, max_size) ndarray
+        Entire position with zstacks as first axis
+        slices: tuple of two slices
+        Each slice indicates an axis to index
+
 
         Returns
         Trap for given slices, padded with median if needed