I have a new never opened RCBS precision scale check weight set for sale. Have you ever wondered if your reloading scale is accurate to more than "O"? This is how you verify that. These measure in grains just like your scale. There are 2-20gn, a 10gn, a 5gn, 2-2gn, a 1gn, and a .5gn weight in this set. Very critical to know if your scale is calibrated and giving you accurate readings. I can meet in Bountiful some days if it helps.