With sockets and switches should consider when renovating not save, the dust and dirt when the subsequently installs you really do not need. That is why I planned the same a little more generous in the renovation of my hobby room and the existing electrical system completely replaced. Overall, about 25 flush-mounted boxes for switches and sockets were put. I bought the hollow drill, because I did not want to lift all individually the holes. At 2-3 doses that goes safely, in more that lasts too long. The drill bit comes in a good-sized plastic package, which unfortunately is only good for the recycling bin. Too bad that is not equal to a storage box. The crown itself is screwed and can be exchanged for other diameters. The grip in the chuck is good, the other parts remained firm while working. I have used the drill bit just in old-brick walls. As the work in concrete is I can not judge, but the bricks are partially see different hardnesses. Thus, the hole should not be able to drill with high speed. Unfortunately, the pilot bit is a bit short, so one with thick plaster not yet reached the stone and somewhat leaderless in the "sand" swirls. The core usually breaks even from, but he also has some male wedged in the beads and had to be herausgeporkelt with a screwdriver through the holes. The drilling depth is sufficient so just for the deep junction boxes. Wear I can not see for the 25 holes, the brazed carbide tips are all still there. For smaller projects, the quality is absolutely sufficient.
