Depth adjustable bit holder with quick change chuck. Knurled adjustment and locking rings. 1/4″ (70mm) hex drive. 1/4” (70mm) hex socket. Wide face reduces damage to work surface. Depth adjustable bit holder with quick change chuck. Knurled adjustment and locking rings. 1/4″ (70mm) hex drive. 1/4” (70mm) hex socket. Wide face reduces damage to work surface.