Aluminum Alloy Heavy Duty: Aluminum alloy is a main component of aluminum.Aluminum has the characteristic of light weight.Thats why the quick release skewers are made of high strength aluminum alloy that is not only sturdy but also lightweight.The service life is very long. Lightweight and Durable: This quick release skewer is made of aluminum and plastic, and weighs 3.6 oz (106 g).Aluminum components are made of iron and copper, making this standard hub skewer exceptionally durable, reliable and reliable