This is a replaecment Arrma 57 Tooth HD 0.8MOD Spur Gear for use with the Arrma 3S BLX Big Rock, Granite, Senton and Typhon. 

 - Arrma Big Rock 3S BLX
 - Arrma Granite 3S BLX
 - Arrma Senton 3S BLX
 - Arrma Typhon 3S BLX
 - Arrma Vorteks 3S BLX