For about 5 years I've been buying sheets of prismatic material from Home Depot and cutting 3 inch circles on my drill press for a gadget I make and sell. I don't know how I've never ran across this site. These are perfect! Already cut and accurately sized, plus they're a lot, (maybe twice?) thicker than the ones I was getting at the store. Shipping was very fast. Everything about this purchase was better than expected.