They are Powergrip GT2 belts, the manufacturer Gates claims that the tooth profile is supposed to be one of the strongest, and capable of carrying a significantly higher load than their HTD belts.
SH Z-Car, Custom Crawler, 8s Savage, 12s XTM XLB 1/7 buggy, 4wd 4-link rear/IFS Pro4 truck, Custom Hyper 10 Short Course, Belt-Drive Mammoth ST 1/8 truggy, 4s 17.5 MM Pro HPI Blitz