Gates K030334RB Blue Racing Micro-V Belt Belts are precision ground, not cut, so they fit the pulley with absolute perfection 3 Ribs, .42 inch (11mm) top width, 33.46 inch ( 850mm) effective length, 34.024 inch (864mm) outside circumference High-modulus, low-stretch polyester means Herculean strength for high load-carrying capability Aramid reinforcement in a patented EPDM compound for three times the heat resistance and durability of standard belts Patented EPDM compound gives Gates Racing belts extended service life