I sell Gates Extreme belts that work awesome and around 60.00 shipped.
I have sold a ton of these belts with no problems. They are not double cogged and are a harder compound belt, I have never had one that slipped due to the harder compound, they hook up great. I have run these for years on my personal sleds varying from 700, 800, to 900's in the Gen II, Edge, IQ, and Raw chassis.