Vortex 520 Steel Rear Sprocket BMW F750Gs / F850Gs / F900R / F900Xr / M1000R / M1000Rr / S1000Rr / S1000Xr Made of the high carbon steel for maximum strength. Features: 100 CNC machined Saber tooth grooved Vortex patent pending design Carbon steel construction Laser cut Durable satin finish Longer lasting than aluminum sprockets Weight saving cut outs Now available in black hardcoat (Ptfe), proven to last up to 30 longer Note: Image is for reference only.