I 've tried the opt polish, opt compound and the ssr2.5. I got better results with ssr2.5 with the PC and opt prouducts with a rotary. I don't know if its because the opt polish needs more heat or what but I wasn't able to get the results I wanted when using it with the PC. When using the ssr2.5 with the PC I can get the same results as the opt polish and a rotary and both are great results.