This brake, suitable for the most market models, strong braking force, do not hurt the disc. It is a fine choice for cycling enthusiasts.    Features:  Dual piston driving principle, drive friction disc on both sides at the same time, brake disc automatically return to position, equal force on both sides, synchronous friction, stable brake, strong braking force.  Three-dimensional cylinder design, vertical cylinder can provide a larger piston in a shorter distance, a gentle pinch can easily brake.  Resin to make the disc, do not hurt the disc, further improve the braking effect.  Practical aluminum alloy material, quick brake, timely reset.  Three-finger brake handle for easy operation of the brake.    Specifications:  A column: 75mm  B column: 51mm  Material: aluminum alloy  Type1: a pair of black oil brake (front and rear)  Item weight: 630g / 1.4lb  Package weight: 650g / 1.4lb  Type2: a pair of black oil brake (front and rear) + a pair of disc brakes  Item weight: 830g / 1.8lb  Package weight: 850g / 1.9lb  Type3: single black oil brake (right front)  Item weight: 300g / 0.7lb  Package weight: 320g / 0.7lb  Type4: single black oil brake (left rear)  Item weight: 330g / 0.7lb  Package weight: 350g / 0.8lb  Type5: single black oil brake (right front) + single disc brake  Item weight: 400g / 0.9lb  Package weight: 420g / 0.9lb  Type6: black oil brake (left rear) + single disc brake  Item weight: 430g / 0.9lb  Package weight: 450g / 1.0lb  Package size: 250 * 200 * 50mm / 9.8 * 7.9 * 2.0in    Packing List:  Type1:  1 * Pair Of Black Oil Brake (front and rear)  Type2:   1 * Pair Of Black Oil Brake (front and rear)  1 * Pair Of Disc Brakes  Type3:   1 * Black Oil Brake (right front)  Type4:   1 * Black Oil Brake (left rear)  Type5:  1 * Black Oil Brake (right front)  1 * Disc Brake  Type6:  1 * Black Oil Brake (left rear)  1 * Disc Brake