- Heavy Weight for the mini crawler, add 18g to each wheel and help the crawling performance. - Compatible with: FMSmodel FCX24 both front and rear axles. (will fit FCX24 stock wheels and TREAL 1.0 beadlock wheels, if you use other wheels please check the clearance first, thanks) - High quality brass material. - Precision CNC maching, perfect fitment. - Black coating to prevent brass oxidation, looks better. -Outer Dia. :22mm (0.866inch)