Who hasn't got a buggered up crane lock screw? Now, you can replace it. This is a new reproduction replacement crane lock screw (replaces part number 50902D) for early Colt D frame revolvers. Commando, Agent, Cobra, Detective Special, Diamondback, Police Positive, Viper, .32 New Police, .38 New Police, .38 special double action revolvers, and more. Photo 3 shows the screw in action - crane lock NOT included.