Features: Aluminum alloy rear disc brake, durable and useful. With strong braking force. Smooth and stable control. Excellent heat dissipation effect. Easy to install and remove on your bike. Specification: Condition: 100% brand new Material: stainless steel Color: red, black (optional) Size: approx. 7*4.5cm/2.8*1.8inch Package List: 1 x Disc Brake Caliper Installation method: 1. Loosen the screws and install the rear calipers on the disc brake bracket of the frame. Press the torque lock. Check that the caliper part is free to move. 2. After the brake line is fixed, make sure that the excess line does not exceed, and cut off the excess line. 3. After fixing the brake line, lower the catheter and put the catheter back in the correct position. 4. Before installing the wire, make sure that the jug integrator is all screwed to the bottom. 5. The ideal ratio of the dish to the outside of the groove is 1/3 and 2/3. 6. Turn the knob clockwise inside (near the wheel) until the disc is in the correct position inside the caliper. Please note that the dish is not centered in the caliper.