A-Grade Locks: A-grade anti-theft locks commonly use A-shaped and cross-shaped keys. The internal structure of A-grade lock cylinders is simple, with minimal variations in the pin tumblers and shallow keyway slots. These locks can be easily opened within one minute using certain techniques. The ball structure of A-grade locks consists of either a single row or a cross pattern of spring-loaded balls.

B-Grade Locks: B-grade locks feature a flat key with a double-row pinhole. Unlike A-grade locks, the key surface of B-grade locks has an irregular arrangement of slanted lines. There are three main types of B-grade lock cylinders: computer double-row cylinders, double-row dimple cylinders, and double-leaf cylinders. These locks can typically be opened using twisting tools within five minutes, and they often share high cross-compatibility rates.

C-Grade Locks (B+ Grade): C-grade locks, also known as B+ grade locks, have a key shape that includes either a single-sided blade with internal milling slots, an external milling slot, or a double-row key with a blade. The lock cylinder type is a sidebar cylinder, and the pin structure consists of double-row blades and V-shaped sidebar pins. If a strong torsion tool is used to force open the lock cylinder, the internal mechanism will be damaged, causing a self-destructive lock that cannot be opened.

A-Grade Anti-Theft Locks:

Only keys with a single row of ball slots are considered A-grade anti-theft locks, with dimple keys and cross keys being the most common examples. The grooves on the key, although not circular in appearance, correspond to the structure of the fingerprint smart lock‘s pin tumblers. The internal structure of A-grade lock cylinders is simple, with minimal variations in the pin tumblers and shallow keyway slots.

B-Grade Anti-Theft Locks:

B-grade locks have two types of keyways, ball slots, and milling slots. These security door locks for homes are commonly paired with flat keys that have a double-sided double-row design. Key types for B-grade locks include single-row bump keys and single-row dimple keys. The internal structure of B-grade lock cylinders is more complex compared to A-grade locks, providing a higher level of security against theft.

(C-Grade Lock) B+ Grade Anti-Theft Locks:

B+ grade locks, also referred to as C-grade locks, are currently considered relatively secure. From the key’s perspective, they typically have a double-sided double-row configuration with adjacent blades or curves. The lock cylinder’s intricate internal structure requires more than 270 minutes for skilled technicians to open, providing reliable security.

Anti-Theft Door Lock Inspection:

1. Check the Security Grade of the Lock: When selecting an anti-theft door, it is essential to choose one with a B+ or C-grade lock cylinder.

2. Inspect the Anti-Theft Door Lock: The smart home door lock should have a steel plate with a thickness of at least 3mm for added protection.

3. Check the Length of the Main Lock Tongue: The effective length of the main lock tongue on the anti-theft door should be no less than 16mm, and it should have a lock tongue stopper. If this feature is absent, the lock is considered substandard.