Yescom 3' Hydraulic Hole Punch Die is designed to be installed on hydraulic punch to drill 3 9/16' diameter actual holes on up to 16-gauge stainless steel, 10-gauge iron, steel, aluminum, brass, Compatible with Yescom Manual/Hydraulic Knockout Punch Kit Made of heat treated 40Cr Steel for enhanced hardness, tensile strength, and rust resistance Ideal for sheet metal fabrication, electric service boxes, wire pipelines Punch Die Dimension(Dia.xH) 4 1/8' x 1 1/8', 3 9/16' x 1 1/8'