raw edge cogged belt: better flexibility, better transmission efficiency, smaller pulleys can be used . very good performance to hear resistance, a: ax,bx,cx, b:xp-series : xpz,xpa,xpb,xpc contruction features: 1: top fabric 2: top rubber ----cr rubber impregnated matt-finishing fabric resists oil and heat. 3: adhesion rubber ---protects the high strength tensile cords 4: tensile cords ----tough polyester cords won't fatique even with repeated shock loads.cords are specially treated to resist stretch and to carry high hosepower demands. 5: compression rubber .----fiber reinforcement in this section is transversely aligned to provide masimum crosswise rigidity for tensile cord support, while allowing for extreme flexibility. 6: cog: ----the cog design provide flexibility to reduce heat build up, minimize cracking, give wide speed ranges, and maximize belt life. please chose the good one by msn: aproautoparts1@hotmail.com