Professional DID The rider, buying the DID Professional chain, is aware that he has chosen the best quality product available on the market, traditionally from which he demands reliability, durability and economy of operation. However, it is always advisable to replace the pinion and crown included in the kit even when the profiles of the teeth visibly seem regular. Kinematics, regular winding, chain-profile tooth roller coupling, must be in perfect harmony, to optimize le performance of the transmission. Otherwise the gear damages the chain, le regular joints, accelerate the process of degradation of the crown itself. Normally inside the si kits use gears from Sunstar Japan and le chains are in many cases sophisticated or of higher quality class pithe same DID provided in the first equipment. And that's why Professional's DID kits are a safe, reliable, long-lasting reference recommended by the best experts in the industry. This prestigious product is intended for pidemanding users, accustomed to long journeys and that does not disdain even a sporty use of the bike. The kit includes chain mount/disassemble chains and spray lubricating ognibene Pinion: 16 teeth Crown: 46 teeth Chain DID 520 110 Meshes