Hollow stems are CNC-machined from the highest quality 6061-T6 aluminum. They feature a skeletal design that keeps the weight extremely low, while maintaining a high level of strength. A 53-millimeter extension stem weighs just 215 grams/7.6 ounces. The most unique feature of the stems is the mid-bolt wedge mounting system. By removing the rear pinch bolts and moving the mounting bolts to the middle of the stem, we reduced the weight and overall bulk, as well as eliminated a significant hazard to the rider’s knees. The stems come in 48- and 53-millimeter sizes and can be run with a 5-degree rise or flipped over with a 5-degree drop. To ensure proper clamping force, the stem must be mounted on a fork with at least 40 millimeters of exposed steerer tube above the headset or upper spacer. Your stem should be installed by a professional bicycle mechanic. Available in anodized red, blue, gold and black with laser-etched graphics and six hollow chromoly Allen bolts. Meets or exceeds ENBMX standards. Fits standard 22.2 Ø handlebars.