Material: abs HD Safety Bicycle Convex Mirror: The MTB rear view mirror has a convex lens for a wide field of view and can be adjusted to any viewing angle. Be sure to remove the protective film before using the bicycle mirror. 360 Degree Rotation: The bicycle mirror has 360 degree omnidirectional rotation, which can be adjusted to any direction to help you see in all directions. Better fit in all directions to see all directions of your back for a safer ride. EASY TO INSTALL: Install securely in minutes 1. Mirror the surface at an angle to attach the handlebar end 2. Fully insert the expansion bolt of the attachment point into the handlebar end 3. Use an Allen key (included in the package) to tighten and adjust to the desired location. Short single package size 7.3*3.2*10.4cm Short double package size 12*10*5.2cm Long single package size: 18*7.5*2.5cm Long double package size: 18*7.5*4cm