This is the Robinson Racing 1/8" to 5mm Reducer Sleeve. This sleeve will allow you to use 5mm bore pinion gears on motors that have an 1/8" shaft.Robinson Racing 3.17mm to 5mm Reducer Sleeve (1/8" to 5mm) RRP1200 HHSKU: RRP1200$7.50PriceQuantityAdd to CartBuy Now