Wow! We have used a few of these with our orbital sander and I am happy to report that these work just as well as name brand sanding discs at a fraction of the price. I will be back when we run out. You receive 100 pieces with 5 sets of 20: 80, 120, 150, 180, 240. With all of these included, you can work on most projects from start to finish with ease. I highly recommend adding these sanding discs to your stockpile so you never run out.