Computer-designed to achieve ultimate strength at minimum weight JT combines leading-edge technology with top materials to produce the ultimate quality sprocket range with unbeatable value Every sprocket meets or exceeds the highest possible quality standards set for the motorcycle industry Sprockets are heat-treated and bead-blasted to reduce material surface tension Front sprockets are made with C45 steel and SCM415 chromoly steel alloy; rear sprockets made with top-quality-grade C45 high-carbon steel RUBBER CUSHIONED FRONT SPROCKETS "RB" Used by the major Japanese motorcycle manufacturers since early 1990Æs to dampen the chain impact on the teeth of the front sprocket Quality, design and OEM proven technology are the same as used for what is supplied to the motorcycle manufacturers INDUCTION HARDENED BLACK ZINC FINISH REAR SPROCKETS "BK" Made from C45 high carbon steel Teeth ARE heat-induction hardened to 38-50 HRC When installing sprockets which differ from OEM sizes, check for proper clearances before operating. instruction to designerboxed note follows.. SPROCKET FRONT 14T 520 RU