The durability of door lock is a specific index to measure the service life of lock and key, and the firmness is a comprehensive index to measure the endurance of tension, compression and torsion of riveted parts and assemblies in lock structure and the service life of lock and key. The number of keys that actually open is the number of keys that differ from each other. The larger the value, the higher the lock density. Flexibility is a technical index to determine whether locks are easy to use. It includes the opening and closing of locks, the insertion and pulling of keys, the activity sensitivity of locks, handles, lock tongues and other transmission parts.
Door lock confidentiality refers to the safety and reliability of the lock after closing and the ability to prevent foreign body from opening. Each group of keys of the lock has different number of teeth and the rate of opening each other is an important index. Different types of locks also stipulate different safety devices and defensive measures. In the same kind of lock, the key to open a non-serial number lock is called mutual opening. The smaller the value, the higher the lock density. It is the most important index to evaluate lock quality.