Lock bodies are described in different ways around the world, which makes cross-border ordering confusing. This reference table puts the common names side by side. It is a guide, not a guarantee: always confirm with a drawing or photo.
Free tool: enter your backset and centre distance in the Lock Body Finder to see which standard your door matches.
Printable: a one-page lock body cheat sheet (PDF).
How the names work
- Chinese numbers (6068, 6085, 5072): the first two digits are the backset in mm, the next two the centre distance between spindle and cylinder in mm.
- DIN 18251 designation (55/72/8): backset, cylinder-to-spindle distance and spindle width in mm.
- US sizes: backset in inches (2-3/8 or 2-3/4) and bore diameter (2-1/8 inch cross bore), for deadbolts.
Reference table
| Name | Backset | Centre distance | Where common | Our option |
|---|---|---|---|---|
| 6068 | 60 mm | 68 mm | Chinese security doors | 68 body: automatic and handle locks |
| 6085 | 60 mm | 85 mm | China, Russia and neighbouring markets | Rear-lock option on 68-body models |
| 6090 | 60 mm | 90 mm | Selected markets | Rear-lock option on 68-body models |
| 5072 | 50 mm | 72 mm | Selected markets | Rear-lock option on 68-body models |
| 5050 | 50 mm | 50 mm (by the same naming) | Wooden interior doors in China | B6, B36 (5050 body) |
| DIN 55/72/8 | 55 mm | 72 mm | Europe | No identical match; compare 5072 and B7 options |
| US deadbolt | 60 mm (2-3/8 in) or 70 mm (2-3/4 in) | 2-1/8 in bore | North America | D3 smart deadbolt |
Reading the table
The same number can mean different bodies. A 6068 body from one manufacturer may differ in faceplate and bolt arrangement from another. Faceplate width and length matter as much as the two main sizes.
Similar is not identical. The 5072 option and the European 55/72/8 share a 72 mm centre distance, but the backset differs by 5 mm and the spindle may differ. Never assume a match.
The D3 and US doors. Our product data lists the D3 for doors of 35-50 mm and shows it replacing ball locks and old deadbolts. Bore and backset are not listed, so confirm them before ordering.
Steps to confirm fit
- Measure backset and centre distance on the existing body.
- Photograph the faceplate and note its width and length.
- Record door thickness and handing.
- Send the data to us and we confirm the option.
See the regional guides in the buyer map and the full compatibility page.
Frequently asked questions
What does 6085 mean?
By Chinese naming it is a 60 mm backset with an 85 mm centre distance.
Is 5072 the same as the European 55/72/8?
Not exactly. The centre distance is the same at 72 mm, but the backset is 50 mm instead of 55 mm.
Can you confirm fit from a photo?
Yes, send photos of the door edge and body with measurements and we will confirm.
