Only the bullet slot on the key is a class A anti-theft lock, of which the digit keys and cross keys are common. Although the lines on the key do not look like dots, the corresponding lock core is a marble structure. The internal structure of this lock core is very simple, limited to the changes of the marbles, and the bullet grooves are small and shallow.
Class A lock key
Within one minute of the A-level lock-proof technical opening time, the mutual opening rate is extremely high. The marble structure is a single-row marble or a cross lock.
Class B anti-theft lock
The key has both a bullet slot and a milled slot. It is a B-level lock. This lock is generally equipped with a flat key, which is double-sided and double-row. The internal structure of the lock cylinder is more complicated than that of the A-class lock, and the anti-theft property is more secure than the A-class lock.
The B-level lock key is a flat key with double rows of marble slots. The anti-technical opening time is within 5 minutes and the mutual opening rate is high. With a strong twisting tool, the lock cylinder can be opened in 1 minute.
Class C anti-theft lock
Super B lock is the current level of security. From the perspective of the key, it is generally a double-sided double-row bullet slot, and there is a blade or curve next to it. The lock cylinder has a strict and complicated workmanship. The relevant departments monitor the technology for more than 270 minutes. It can be used with confidence.
The shape of the key is a single-sided blade milling slot, and the marble structure is double-row blade plus V-shaped side column lock. If the lock core is opened with a strong twisting tool, the lock core is damaged internally, and the lock explodes, causing it to fail to open.