The One Piece Full-Length Guide Rod replaces your stock recoil guide without pistol modification. Assembly and disassembly are the same as with stock components (however a bushing wrench is required). Some shooters are in the habit of moving the slide back slightly to remove the barrel bushing, this is not possible with a one piece guide rod. CAUTION: Safety glasses should be worn at all times when replacing or working with firearm springs. Failure to follow this safety precaution could result in bodily injury. Due to the varying recoil spring tunnel lengths on some brands of pistols ensure that your firearm is compatible with parts built for a 4.25" barrel Commander style handguns. Guns with short recoil tunnels and full-length rails like the STI 4.1 series are not compatible with Commander recoil system parts.