This Pinion Gear, 34T Mod1 Safe-D8 is compatible with the Arrma 1/5 Kraton 4WD Extreme Bash Roller (ARA5208, ARA5208B) Arrma 1/5 Outcast 4WD Extreme Bash Roller (ARA5210, ARA5210B) and the Arrma 1/7 Limitless V2 Speed Cash roller (ARA7116V2).