1, never rust bearings, theoretical assessment, if not damaged, can be used for about 200 years. 2, withstand the impact of a large, special forces warriors, jumping from a height of 100 meters, by rolling to the ground, bending the knee and hip joints, etc. will be weight impact buffer, not only no injury, and can immediately stand up, immediately into battle. If the injury, found joint rattling, painful activities, please promptly seek medical advice to save your valuable joints and avoid artificial joint replacement.