SincereetaliThis 5pcs countersinks are not suitable for drilling less than 25HRC hardness workpieces, such as iron sheet, carbon steel, PVC board, wood, insulation board, etc..? Features:? 6pcs includes 5 bits for drilling pilot holes for screws sizes #5 #6, #10 and #12 and #8, 1 hex key. Special designed countersink countersinks HSS steel counter bores & counter bores pilot holes. Adjustable counter sleeve depth with an allen key. Adjustable length countersinks for screws of different lengths simply by loosening the clamping screw. Pre-drilling and countersinking to sink screws flush with the surface material or deep counter hole boring for screw heads below the surface of the pipe. Super sharp cutting flute effectively clears chips and leaves a clean & smooth hole. Adjustable drill bit length for desired screwed depth and features a flattened shank for a slip-free countersink connection. Specifications: Color: Gold + Black Material: Carbon Steel + High Speed Steel Hardness: HRC 60 Countersink Sizes: #6, #8, #10, #12, #14 Shank: 1/4 Hex Shank Quantity: 5pcs with drill bits + 1pc small wrench Chamfer diameter: 10mm/0.39in Countersink diameter: 6# 2.38mm/0.09in 8# 2.78mm/0.11in 10# 3.175mm/0.125in 12# 3.56mm/0.14in 14# 3.97mm/0.16in Item weight: Approx. 58.5g/2.06oz Package size: Approx. 7 * 5 * 1.1cm/2.78 * 1.97 * 0.43in Package weight: Approx. 60g/2.12oz