I bought this product for mounting my kitchen and small screwdriver drill work with Bosch cordless percussion PSB 18 LI-2 that I bought together this package. The tip to screw begins to wear when I mounted furniture only 5 or 6 !!! 1 drills for metal broke on first use in trying to break a stainless steel sink with a thickness less than 4 mm without even a hole !!! Drills Concrete (I do not know if the drill or not) but on simple concrete pierces it very difficult but not on the hard concrete Drills wood, c alone with whom I have not had any problems.
I highly doubt the origin of this case, not c Bosch ??? !!!!! I strongly advise you to buy them despite the attractive price because you will end up with only usable wood drills
