Which belting?

I am soon going to buy the rough top belting for our wheels this year, but I was wondering which material works best. I am thinking neoprene or natural rubber, but as we have never used belting, I have no experience to base my choice off of. I am hoping to order today so I can tell my drivetrain team tomorrow what we are using. As for why we’re so late ordering stuff, we only got our tools to our new room this Tuesday.

NVM I ordered neoprene and SBR.