Bought this set about a week ago. I'm a life mechanic and should have known better. I bought this set to use on RC cars with my son. I used this set for the first time last night and the 1.5mm bit was completely worn out by the end of our little upgrade project. I have never used these bits for tightening screws, only for removing screws and screwing them back in. I always hand tighten the bolts on our RC cars to get the required torque due to the plastic parts on RC cars. They're cheap, so there they are. But they're not worth their money if they wear out after minimal use. I've just ordered a set of MIP driver bits and I'm sure I'll be a lot happier now.