I am not sure if you are reffering to the utility belts or not. They are belts that are used on items like table saws and furnace blowers. Any hardware store or simular larger home depo etc should have a selection of utility belts. I had a peek under the hood late yesterday and it looks like 39 inch belts.

There are so many numbers on those belts I am not positive though. Take along an old belt for comparison. They are cheap as well.