The quality of these countersinks is fairly good with nice edges on the cutting flutes and a wide range of sizes to suit most applications. I've used them on aluminium, wood and plastic (ABS and HDPE) and the results are excellent. You can also use them on steel, but remember that as they are only made of high-speed steel, the life of these bits will be greatly reduced. For all other materials, however, this is excellent value for money.
MICHELIN Latitude Sport 3 235/60 R18 103W summer
22 Review
Bit and socket set BOSCH Promoline (2.607.017.322), 26 pcs.
24 Review
Cordless drill driver BOSCH GSR 120-LI (06019G8020/06019G8000)
54 Review
Tool set Stels Tool set, 1/2", 1/4", CrV, plastic case 94 pcs, Stels, 94 pcs, black
45 Review