TCT core drill with threaded wall for heavy duty drilling variou concrete, brick, ... used to increase that drilling efficiency.Femal M22 Threaded Connecting for different arbor and adapter with male ... M22 threaded connecting. For threaded wall type TCT core drill, the flat ... , male15Threaded7011.160722216072M22, male15Threaded TCT Core Drill 72mm Threaded Type