This Pinion Gear, 31T Mod1 Safe-D5 is compatible with the Arrma 1/7 Limitless All-Road Speed Racer (ARA109011), Arrma 1/5 Kraton 4WD Extreme Bash Roller (ARA5208) and Arrma 1/5 Outcast 4WD Extreme Bash Roller Stunt Truck (ARA5210).