I literally sent them back the next day the quality was so bad. Some bits were missing the chamfer on the face to center them in the hole, but that didn't matter as the bit centering holes were literally OFF-CENTER! Almost all drills were bananas and not a single drill turned directly in the drill. The springs were also weak. Large bits are pretty much useless as the bit is almost the same size as the collar. Just save yourself the frustration and buy the real deal, I have vix (or vicks) and they work great.