The 5" bit is optional shorter bit for 1815C. It is for applications where access is limited. Part number 38151SM.

If the standard 6" drill is too long for your application, this is the optional 5" screw machine drill bit. The 5" screw machine drill will have to be turned by hand with a 12 point socket or wrench. The diameter will not fit a drill motor. The standard drill length is 6" with a 1/2 shank. The 1815C is needed to use this bit and is available separately.