Vortex 654 Black New V3 520 Rear Sprocket: Lightweight Cat5 aluminum racing sprocket. 100 CNC manufactured in the U.s.a. Specially formulated alloy per Vortex specifications. Saber tooth grooves unique tooth design increases sprocket longevity. Vortex patented sprocket design is different than any other sprocket. Features Note: Sprocket shape and size will vary depending on model, picture is for reference only Note: Designed for 520 size OEM replacements or suitable conversions to 520 size chain and sprockets