The Model 637 Chief's Special Airweight uses an aluminum alloy frame with a stainless steel cylinder and exposed hammer. Rated for +P ammunition, it updates the original Model 37 with stainless components and +P capability. Type: Revolver Action: Double-Action Caliber: 38 Special +P Capacity: 5 Year introduced: 1996, USA Weight: 15 oz Overall length: 6.3" Status: Active Intended use: Concealed Carry / Backup