Features: Combination offers precise and consistent shifting performance with an ergonomic shift / brake lever shape. 3 x 7- speed / 3x8-speed compatibility. Ergonomic shift/brake lever combination. Noise-dampening bumper stopper. Visibile Optical Gear Display indicator to confirm the gear position with number at a glance. Compatible with liner-pull, cantilever, roller, and mechanical disc brakes. For Bike Type: Mountain Bike, Trekking Bike, ross Bike, Hybrid, Town Bike etc. Specification: Material: Aluminum alloy Colour: Black Aperture: 22.2mm Gear explanation: 21 speed: 3 front and 7 rear 24 speed: 3 front and 8 rear Package included: 1 Pair bicycle gear shifters