Accurately retro fit standard 2-1/8” crossbore holes with the through bolt holes required by Sargent 10 Line Grade 1. Will also retro fit the U. S. Lock, Arrow RL Lock and IDN Distributors grade 2 levers and other imports using 2-5/8” centering and 5/16” through bolt holes. This unit through bolts to door using the exidting 2-1/8" crossbore for alignment. All required mounting and function holes are located with hardened drill bushings on both sides of template to allow drilling from either side of door. Standard drill guide will accommodate doors up to 2" thick.