They work just fine for their intended purpose, just plan on +/- 0.005". They're made of stamped steel. I've bought two packs of these Empi 0.090" shims and measurements between the two packs varied from 0.085"-0.092", good enough to get you in the ballpark but too unpredictable for precision if you're running a tight deck already. If it really matters, get better quality or custom cut shims. These work on a budget or in a pinch though.