The most secure lock cylinders have been upgraded to Grade B and Grade C; it's best to choose Grade C when purchasing.
Previously, the quality of a lock cylinder was judged by the number of teeth on the key. However, the main focus should be on the cylinder's structure. A leaf-type cylinder with side pins is often much better than a traditional pin-type cylinder. It's best to consult a professional before choosing a lock.
When choosing a lock, weigh it. The heavier the lock, the better the quality of the cylinder, and the more pins it contains, the better its anti-theft function.
When selecting a lock cylinder, look at the color and compare the luster and workmanship. High-quality lock cylinders are electroplated, resulting in a smooth surface and bright color. A deep yellow color indicates a copper core, which is more robust and has better anti-theft performance. A dull, grayish-white lock cylinder with bubbles indicates a zinc alloy core, which has average anti-theft performance.
A key that gets stuck when rotated into the lock cylinder indicates poor anti-theft performance. If the key gets stuck after being partially inserted, apply 5-7 parts force to rotate it clockwise or counterclockwise while continuing to push it into the lock cylinder, it indicates poor anti-theft performance. A key that can be easily inserted into the lock cylinder in a partially rotated state indicates good anti-theft performance.