I bought these to mainly be used on a lesser used machine in the shop, I really didn't expect them to be anything great but for the cost I didn't figure I could go too wrong. I was actually pretty impressed by the holders, the endmill holders all had less that .0004" of runout and the er holders and collets all had less than .0005" of run out. The only holder I was not impressed with was the keyless chuck, it has up to .010" of runout at certain diameters when checked with gauge pins. This entire set cost less than a name brand set of just the collets so overall it is a great value and I would recommend it.