How to use Aluminium locked carabiner-2

Change the carabiners when the following situation occurs
1 when the  abrasive wear place reachs the 1/4 of diameter of the carabiner
2. When the lock section of the hook cannot be switched successfully
3. When the screw of the lock door can not normally closed and turn on.
4 when the main lock is contact with the chemical
5. When the main lock falled from high to solid ground
6 when the main lock is strongly impacted
7 Please consult from customer service if you are not sure whether the main lock can be used anymore.