The Model 637 CT (Crimson Trace) features factory-installed Crimson Trace LaserGrips on the standard Airweight J-frame, providing a laser aiming system that activates upon gripping the revolver. The combination of alloy frame and integrated laser makes it one of the most popular defensive revolvers in production. Type: Revolver Action: DA/SA Caliber: .38 Spl +P Capacity: 5 Year introduced: 2004, USA Weight: 15 oz Overall length: 6.3" Status: Active Intended use: Carry, Backup, Home Defense