One stem fits 2 handlebar diameters Special shim provides fitment for 31.8mm bars, and when removed, allows use of 35mm bars Intelligent no-gap clamp design in the bottom ensures no pinch points, and provides equal clamping force for safety and stability The stem has been certified to the E-Safety Level with Category 5 (Maximum) and passed the EFBE E-MTB Tri Test (EPAC MTB-GR) Aluminum 6061 T6 137g including shims TECH SPECS Model Black One D-2 Direct Mount Bar Dia. 35.0 or31.8mm Rise 21mm Length 45mm Color Black