For locks, when turning the lock, the smaller the sound, the better. When the handle is turned a little, the lock tongue should follow a little. In terms of key shape, pit-shaped key locks are safer than tooth-shaped key locks, but if the pit-shaped key is lost, it must be replaced by the original factory. The more square tongues a lock has, the better the security.
 
    Consumers should pay attention to the following points when choosing locks:
 
    You should choose products from companies with high reputation, stable quality and good after-sales service.
 
    Observe the appearance and quality of the product, including whether the lock head, lock body, lock tongue, handle, cover plate parts and related accessories are complete, whether the surface color of the electroplated parts and spray-painted parts is bright and uniform, and whether there are any signs of rust, oxidation or damage .
 
    First check whether the packaging of the purchased product is fully marked (including product execution standards, grades, production company name, address, production date), whether the packaging is firm, and whether the content of the instructions is consistent with the product to prevent exaggeration and inconsistency with the facts.
 
    To check whether the function of the product is reliable and flexible, you should choose two or more products for comparison and inspection. Especially when purchasing two-way lock products, you must use all keys to test the opening and closing of the inner and outer locks respectively. It is recommended that each lock has at least Try three or more times.
 
    The mutual opening rate is the mutual opening ratio of the lock and the key. The fewer locks opened by one key, the stronger the safety and reliability of the lock. When purchasing, consumers should try their best to choose a lock with a large number of key teeth, because the more teeth the key has, the greater the difference and the lower the mutual opening rate of the lock.
 
    Choose the lock according to the use environment, such as dryness and humidity, door structure, thickness, left or right door opening, inward or outward opening, etc.