7 piece set includes bits for drilling pilot holes for screw sizes 3mm, 4mm, 5mm, 6mm,7mm,8mm,10mm.
Made of HSS 4241, built to last. Chamfer is 5 flutes that can discharge the wood more rapid in the process of using, sink hole disposable drilled smooth, screw cap perfect embedded in the surface of work piece.
Special designed steel counter sleeve countersinks or counter bores pilot hole.
Drilling length can be adjusted for various length screws (comes with a handy wrench for your convenience)
Suitable for aluminum, wood?hardness less than 25 degrees? and plastic, ideal for production, maintenance or portable drilling jobs.