Weird lock with 'A', 'B' and 'C' keys.

[Europrofile101]

Hi, newbie here, been lurking for a while but not posted before today. A few days ago I bought a new door off the Internet, With this door came a peculiar lock, a type I have not seen yet. The lock itself looks like a Mul-T-lock Garrison Europrofile dimple lock with 7 pins however it came with 8 keys, of 3 different types and instructions written in 'Engrish' (English badly translated from another language). Here are the instructions as written:

USE CAUTION:
1:B keys are used some other persons;
2:The key C and A keys is used Masters, Bosses and Landlords;
3:The key C is put into the lock body and circumgyrated,B keys are invalidated.
MARK
1:Please inspect A keys and the key C of allvalidity;
2:Before the master using it,it's tabooed to attempt to use key C to open the lock

I think what is happening is that the 'B' keys are for 'fitters' for installing the door, once the door is installed key C is inserted into the lock and turned which permanently modifies the lock somehow so that the 'B' keys don't work and the 'A' keys do work.

Has anyone here seen such a lock before, is there is techincal name for them?
Any idea how it works?
Anyway the door is currently still packaged and it's very heavy (15 point locking steel door). But when I get it out I will be able to have a closer look at the cylinder. I may not keep this lock and replace the lock in the door with an Abloy Protec keyed alike with my existing protecs.

[globallockytoo]

Have you ever heard of construction keying?

[Europrofile101]

Have you ever heard of construction keying?

I have now

[Squelchtone]

Mul-T-Lock actually sells this as their "3 in 1" product.

http://www.mul-t-lock.com/res/English_Product_files/Introduction/3_in_1.pdf

It's interesting you seem to have found a generic one. Sure it isn't real Mul-T-Lock?

welcome to the forum!
Squelchtone

[Europrofile101]

Not seen that mul-t-lock before.
The face of the cylinder I have is blank, It does not have the familiar 'mul-t-lock geezer' or any other brand on it. I suspect it is possibly a Chinese knock-off. Going by the Engrish instructions and the Chinese writing on the box of the door I suspect the door and the lock are of far eastern origin. While the keys I have look like mul-t-lock garrison keys I don't have a genuine mul-t-lock key to try in it so I cannot say if it is compatible.

[Rickthepick]

probably a wan and jia or some other chinese lock