Reverse Black One D-2 Direct Mount Stem (31.8/35.0) 45mm BlkOne 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