It’s not easy to make a perfect instrument hole, but this tool will make it a snap. It’s a punch made out 4140 tool steel that has been hardened and precision ground to produce clean, flawless holes in aluminum up to 1/8” thick. Dual reversible design for punching both 2-1/4” and 3-1/8” holes. The template is a die-punched steel drill guide that fits into the instrument hole and allows you to precisely drill the mounting holes.