Great upgrade solution for cyclists who prefer their computer above the stem. Designed with mountain biking in mind, but also ideal for cyclocross, triathlon, or bike touring. CNC-machined aluminum for low weight and strength. Compatibility: Garmin Edge 20, 25, 200, 500, 510, 520, 530, 800, 810, 820, 830, and Forerunner 310XT. 1-1/8″ Steerer tube Diameter, Thickness 5mm, Length (Center-to-Center) 50mm. Steerer mount replaces standard 5mm spacer on 1-1/8″ steerers, and is locked securely in place by the compression cap. Made in the USA with a lifetime warranty