Two-way brake system: Pushed by 4 pistons,the bike brake pads will clamp the disc rotor to brake from both side,which prevent the rotor from deformation so as to prolong its life. Features: Left/Right brake lever fit for 22.2mm handlebar. Hydraulic 4 pistons and two-way brake prolong the life of rotor. Integrated brake lever and oil tube prevent oil leak. Suitable for most mountain bikes. Specifications: Model: Front Brake / Rear Brake / Front&Rear Brake / Front Brake&Rotor / Rear Brake&Rotor / Front&Rear Brake&Rotor (optional) Material: Aluminum alloy + Stainless steel Front Oil Tube Length: 800 mm / 31.5 in Rear Oil Tube Length: 1400 mm / 55.1 in Applicable Handle Diameter: 22.2 mm Applicable Rotors Size: 160 mm Package Weight:700g / 24.7 oz Package Size: 25 * 20 * 7 cm/ 9.9 * 7.9 * 2.8 in Package List: 1* Front Hydraulic Disc Brake 1* Rear Hydraulic Disc Brake 4* Long Screw