Quantity 2: PuriTEST 2x2 **ULTRA WHITE** PREMIUM PRO TESTING STONES - $40 Retail Value! Essential for testing gold, silver, and platinum! These specially designed high quality testing ultra white test stones can be washed and used again for hundreds of tests. They are designed specifically for testing and leaves a very visible streak when testing gold, silver, and platinum. These stones will not damage the pieces you are testing. These stones have a rubber backing and are brand new in the original PuriTEST Box! In comparison to the black 2x2 stone, the ultra white PuriTEST stone has increased color change visibility!