diff --git a/small_plastic_headpost_for_mouse/README.md b/small_plastic_headpost_for_mouse/README.md
index 01d6b4f..78c0323 100644
--- a/small_plastic_headpost_for_mouse/README.md
+++ b/small_plastic_headpost_for_mouse/README.md
@@ -9,3 +9,9 @@ Materials needed: Screw and wing nut to hold the clamp to the holder. We had goo
 The holder itself can be made from any abs-like material, the headposts themselves need to be the highest possible strength.
 We used APProto's 'sla xtreme' material with good results (http://www.approto.com/PDFs/Data-Sheets/SLA_XTREME_rev2.aspx).
 Please add more suppliers here if you have tested others.
+
+APProto sometimes has issues with scaling the .STL (usually by a factor of 10). The dimensions for the parts should be as follows. When getting a quote, choose mm as units (rather than inches):
+
+Headpost_Clamp_thinner_inches.stl : 0.59" X 0.20" X 3.15" Vol=0.26" cubed
+
+headpost_holder_for_noga_3_8_inch_clamp : 2.49" X 1.51" X 0.95" Vol=0.79" cubed