From Marcrist
High quality adaptor for use with Marcrist core drills.Adaptor for core drills with 1/2" BSP female thread shank, which are to be inserted on a machine with 1/2" BSP female thread shank. When the adaptor is being screwed tight, the through-hole on the side serves as counter aid.Features & Benefits Drill adaptor High quality Long lasting Type: 1/2" x BSP Male Thread: 1/2" BSP Male Proven reliable Marcrist technology High performace for the home or tradesman