When someone comes to the shop, in need of a belt, we put it up on the bench and try a couple. Nothing beats having the machine right there to try some different belts. Sometimes you can get a round vacuum cleaner belt to work. The lug belts come in 2 grades. If you're sure it's a 12" belt, get the 12.00 "superior" belt, it's a heck of a lot better than the regular belt. Here's a part #1200LT. Retail on these is $5.90.