The stem on your bike connects the handlebar of your bike with the fork, it is available in steel, aluminum and carbon. The stems are particularly important as an adaptation of the steering geometry as well as the steering economy.
There are stems therefore in numerous variants, which differ in the length, the angle and the type of fastening. The differences in length and angle are important for the adjustment of your seat position on the bike, the type of mounting is critical to your steerer and handlebar. Depending on which fork system (1 1/8 ", 1 1/4", 1 1/5 ", Direct Mount, Cannondale OPI) you use, the stem must be suitable, the same applies to the handlebar mountings (25,4 / 31 , 8 / 35.0 mm).
The weight starts at a fabulous 70 grams for the lightest specimens, which are artificially milled parts or laminated carbone specimens.