JT sprockets are made from top-quality steel — the rear ones in C45 hardness by the heat induction method, and the front ones in SCM (chrome-molybdenum) steel alloy, fully hardened. The black colour on the rear one adds Extra mileage "endurance" (a ZINC coating) and, combined with the high-performance gold JT O'Ring drive chain, they guarantee more than double the number of kilometres compared with a normal drive set. They are the ideal solution for the professional but for the ordinary user too. Available straight away for the majority of the underbones on the Greek market. The kit includes: Front sprocket JTF273 14 teeth Rear sprocket JTR263 37 teeth JT 428HDR 104 links chain