Specifications: Material: Aluminum alloy + plastic Options: Black garmine; Red garmine; Silver garmine; Black britton; Red britton; Silver Briton; Quantity: 1; Mount Size: Approx.8 x 3.5cm / 3.14 x 1.37 inch Hole Diameter: 28.6mm (Suitable for 28.6mm bicycle stems) Weight: Approx. 19g Package: 1 x Bike Odometer Extender Note: For Garmin (Suitable for Garmin 1000/820/810/800/520/510/500) Brighton R530 Suitable for R330 / R310 / R100)