Professional tool for commercial or occasional use. Use ordinary drill bits with your SDS and drill Comes with 1/2" keyless chuck as well as SDS adaptor for easy application and fitting. Adaptor simply fits into SDS drill as would a drill bit Can be used on ordinary 1/2" drills as well as SDS drills. The chuck has a 13mm (1/2") drill capacity. Keyless so no need to hunt around for chuck keys. Thread size 1/2" x 20 UNF Plastic housing on the chuck with ridges so that its easy to undo and tighten without it slipping whilst trying to change.