Sunstar is the largest OEM and aftermarket supplier of motorcycle and ARV sprockets in the manufacturing world for very major Japanese motorcycle builder since 1946 Constructed of high-quality, aerospace grade 7075 T-6 aluminum Computer-designed weight reduction holes for the best combination of lightness, strength, and stability Exclusive tooth-valley design provides 50% better chain contact area for the best power transfer possible Hard anodized coating for added durability and a superb finish Cleaning grooves added at the bottom of tooth area. SPROCKET ALUM REAR 39T