Wera Tools - 881/4/1 SB Bit holder with variable screw depth limitationFor patio construction, the screws should be countersunk to be evenly flush with the decking. The 881 4 1 bit holder with variable screw depth limitation and felt ring allows for a uniform depth and protects the surface from brush marks. Two spare felt rings included. Features Bit holder for evenly flush countersunk screws in patio construction With adjustable screw depth limitation Felt ring (exchangeable) prevents brush marks on decking Included: 2