All I know is I recently bought some .001 Carbon Techs from Len. They are the best arrows I've ever owned. I always opted for good but not great. 12 arrows on the spinner...11 spin true. 12 arrows with fixed broadheads...11 shoot true. The bad one was good. Never had that kind of ratio before. Usually with my ICS hunters I'd get from 6-9 shooters from a dozen. I bought the last 5 he had giving me 17. Those 5 are all true.