The Box One 31.8 shifter clamp is an accessory that converts any Box shifter to be compatible with modern drop handlebars found on gravel, cyclocross, and commuter bikes. While these bikes traditionally come with clutchless 2-by drive-trains, the addition of this clamp makes the conversion to a more user-friendly and durable Prime 9 drive-train affordable and simple. FEATURES: - Fits All Box Shifters - Matte Onyx(TM) Finish - Fits 31.8 Drop Bars - 2 Piece Hinged Design COMPATIBILITY: - Box One(TM) 9S Shifter - Box Two(TM) 9S Shifter - Box Three(TM) 9S Shifter - Box Four(TM) 8S Shifter SPECIFICATIONS: - Hardware 1215 Steel - Material Aluminum - Compatibility Works with 7, 9, and 11 Speed Systems - Weight 22g/0.77oz