step drill bits, 4 x 4 12 20 32mm triangular tapered drill bits with titanium coated driver

size 3 1 1 72mm the scale on the drill bit is 4 12. 1 72mm 4 20. 1 102mm 4 32. 1 72mm twist drill bit. the drills can handle holes of different sizes strong and rust proof high speed steel made of high quality high speed steel for fast cutting of thin materials. hss is extremely durable and the bit