Countersinking drills not only allow you to make a hole, but also to countersink into the work surface immediately. The drills are made of the durable material HCS 4241. The set consists of four drill bits which can be used to make holes of 3, 4, 5, 6 mm. You can also manually set the depth limit on the drill bits. This is very useful when there is a need to avoid drilling through the material. The seller recommends using these drills with the drill fixed in the stand, as it is hard to center the drills correctly manually.