Here's an entire page from McMaster that has all the specs and info you could want for the traction material:
http://www.mcmaster.com/#rough-top-belts/=19tn91
IFI Wheels come with both the Wedgetop or the rubber Roughtop. Some teams use the blue nitrile for wheel tread, but it's noticeably more expensive, so it may not be worth it for you.