Signswise 31.8mm Cycling Aluminum Carbon Fiber Handlebar Stem This stiff, sturdy bicycle stem is constructed of high-strength CNC machined aluminum alloy with carbon fiber wrapping. Its design makes the handle bar adjust in a perfect position. Suitable for road bike, fixed gear bicycle, mountain bikes, etc. It is the most versatile device you will ever attach to your handlebars. The bicycle handlebar stem has passed extensive life and ultimate strength tests. Diameter Size: 31.8mm. Weight: 170g Easy installation. Long Lasting