RFX Elite 2.0 Rear Sprocket YZ125 250 YZF250 450 99 25 Various Sizes Colour:Blue lab tested built in fracture points Snowmobile lab tested built in fracture points SE R 250 300 18 22 Bike Year Pitch Part Number YZ 125 99 01 520 FXRS 31 48 YZ 125 05 20 520 FXRS 31 48 YZ 125 02 04 520 FXRS 31 49 YZ 250 02 05 520 FXRS 31 49 YZ 250 99 01 520 FXRS 31 50 YZ 250 05 20 520 FXRS 31 50 YZF 250 01 04 520 FXRS 31 48 YZF 250 05 11 520 FXRS 31 49 YZF 250 12 20 520 FXRS 31 50 YZF 400 99 520 FXRS 31 48 YZF 426 00 02 520 FXRS 31 48 YZF 450 03 04 520 FXRS 31 48 YZF 450 10 13 520 FXRS 31 48 YZF 450 06 09 520 FXRS 31 49 YZF 450 14 520 FXRS 31 49 YZF 450 05 520 FXRS 31 51 YZF450 15 20 520 FXRS 31 48 WRF 250 07 14 520 FXRS 31 50 WRF 250 01 06 520 FXRS 31 52 WRF 400 99 01 520 FXRS 31 50 WRF 426 00 02 520 FXRS 31 50 WRF 450 03 20 520 FXRS 31 50 RFX Pro Series Rear Sprockets are CNC Machined from 7075 aerospace aluminium and feature mud clearing grooves for a longer chain and sprocket life