Signswise100 mm Cycling Aluminum Alloy Carbon Fiber Handlebar This stiff, sturdy carbon fiber and aluminum alloy bicycle stem can be used for school and work. Its design makes the handle bar adjust in a perfect position. This is by far one of the best carbon fiber and aluminum alloy bicycle stem which is available for all mountain biking. Carbon fiber and aluminum alloy bicycle stem bicycle stem is the most versatile device you will ever attach to your handlebars. The bicycle handlebar stem has passed extensive life and ultimate strength tests.