[Special Design] The springs are fixed on the nuts so that not easy to lose [Axle] Diameter: 5mm [Material] Steel Axle and Aluminum alloy Clamp [Length] Front:112mm /Rear:148mm [Weight] Front:50g /Rear:55g [Origin] Made in Taiwan. We pride ourselves on product quality. Let us help you if you have any questions, we will be glad to assist you.