MMG DRIVE BELTS, reinforced, same material that bullet proof vests are made of. Kvlr reinforced belts will last longer than a standard belt, they don’t slip easily. Oil and heat resistant | This belt is your best choice for an upgrade. Size 669x18x30 for 49cc and 50cc Scooters Mopeds ATVs and others Product Description 669-18-30 Kevlar-reinforced drive-belt for 49/50cc 4-stroke scooters commonly found with the QMB139 engine. Belt Size: 669 mm Length x 18 mm Width x 30 mm teeth spacing This belt is Kevlar reinforced, Kevlar’s superior performance characteristics reduce belt stretching and distortion that can adversely affect the quality of your engraving while providing long belt life.