How to choose: For example, if your car spring compressed to 26mm ,and fully extended 42(off the ground),you can choose size B(39mm) Features: 1. Effectively solve problem of springs weakness when heavy load & improve performance of shock absorber. 2. Improve driving comfort and more stable during curve corner. 3. Reduce pumping of absorber when passing through road hump or yellow line. 4. Reduce noise and vibration during traveling. 5. Protect shock absorber and suspension system to avoid oil leak. 6. Extend absorber life more than 2 times. 7. Improve braking efficiency. 8. Size for all type of car including lowered spring and adjustable. Installation Tips: 1. Up the car, till the spring be extended totally. 2. Clean the spring, and then spray some water or oil on it (for easy to install the buffers) 3. Install the absorber buffers. Normally, the absorber buffer be installed at the middle hight of the spring Package included:1 set(2pcs) x Spring Bumper Power Cushion