The longest lasting handgun recoil spring made - our testing has indicated that these springs have a service life up to ten times greater than conventional coil springs. Features: Full-Size 5 inches 45 ACP shooting 230 grain hardball equivalent or standard pressure JHP self-defense ammunition with a power factor of 175000 to 195000 Average service life - 40000 rounds Improved recoil spring life Compatible with standard recoil spring plug Compatible with Shok-Buff recoil buffers