I'm still waiting on some other equipment before I can actually use these plates, but they seem to be very accurate in weight. My scale isn't calibrated but using a pretty accurate bathroom scale to weigh myself with and without each plate most of them were < 2% off except the 25s which I measured as being off by 2.8 and 4.4%. According to my scale all the weights are slightly lighter than expected with the 340 lbs kit weighing 334.3 lbs all in. Strangely the 10s were the most accurate with one measuring exactly 10 in my poorly controlled experiment. With my callipers they measure a bit thinner than advertised which is great for loading lots of weight on a bar. I've seen people on youtube claim that there are actually only 2 Chinese manufacturers that make these plates and these look suspiciously similar to much more expensive Rogue plates. My guess is that as a smaller, newer player chisels actually has newer thinner plates than big companies like Rogue which are probably sitting on a lot of inventory of older thicker plates. Anyway long story short great price, reasonable weight tolerances (even if maybe not really the +-1% advertised and very thin for packing weight on a bar.