Every lock—smart or purely mechanical—still depends on one humble component to keep intruders out: the lock cylinder.
In this post we break down the three Chinese national grades (A, B, C) so you can judge for yourself which type of lock deserves your trust.
- What do A, B and C really mean?
| Grade | Typical Key Shape | Internal Structure | Anti-Tech Opening Time¹ | Duplicate-Key Risk² |
|---|---|---|---|---|
| A | Single-row pins or simple cross-cut | 5–7 pin tumblers, shallow grooves | ≥ 1 min | Very easy—photo-based machines can copy in minutes |
| B | Double-row pins or curved slots | More pins + secondary milling | ≥ 5 min | Harder; needs dedicated key-cutting machine |
| C (a.k.a. “Super-B”) | Multi-row, snake or S-curve slots | Blade + sidebar, high-precision milling | ≥ 10 min (industry-leading models > 270 min) | Extremely difficult—billions of theoretical key differs |
¹Source: GA/T 73-2015 mechanical anti-theft lock standard.
²Measured by “mutual-open rate”: A ≤0.03 %, B/C ≤0.01 %.
- Where do SMART locks fit in?
- Cylinder inside
Reputable smart locks use C-grade cylinders by default.
That means the mechanical part of the lock already meets the toughest national standard. - Extra electronic layers
Biometrics (fingerprint, 3-D face), virtual-password keypads, instant phone alerts, and cloud logs add active defense no mechanical lock can match. - Weak links to watch
Cheap models may still ship with A- or B-grade cylinders to cut cost. Always demand a written test report showing ≥C-grade certification.
- Real-world takeaway
- If you buy a high-quality C-grade mechanical lock, you already outrun 90 % of burglars who rely on quick “tech-opening” tools.
- Pair that same C-grade cylinder with smart-lock electronics and you move from “hard to pick” to “actively protected and instantly notified.”
Bottom line:
A smart lock isn’t automatically safer—it’s safer because it starts with a C-grade cylinder and then adds layers. When shopping, ask the vendor two questions:
- “Is the cylinder certified C-grade?” (not just the body)
- “Can I see the GA/T 73-2015 test report?”
Answer “yes” to both, and you’ve locked the door on 99.99 % of break-in attempts.
