Front sprocket, rear sprocket and a precut chain make a convenient kit
Sprockets are made of high-quality steel and have OEM gearing
Chain is Reginas high-performance Z-ring series with gold outer plates and Z40 sealing rings, which dramatically improves performance and wear life; includes both clip- and rivet-type masterlinks
520 conversion kits include all the above, but the rear sprocket is aluminum rather than steel, which in some applications reduces the chain + sprocket weight by as much as 2.5 lb.
See Regina Chain Specifications Chart for chain rating information