Help reading a AKSMU Rear Sight

[incorrigible]

I've bought an supposed AKSMU(not likely) rear sight for a VSS Vitronez clone build I'm working on. It has windage correction and is ranged for up to 1000m (like that'll ever happen with bulk 7.62x39).

However it also has addition ranging tools that is supposed to be designed for the use with suppressed rifles, notablby the PBS-1.

It has readings on both sides of the ranging rail which is also unusual.

Attached are some pics. Can anyone educated me as to how one is supposed to utilize the suppressed ranging tool.

 

[Satain]

If it's for the AK you will find it too long for the VZ but does fit the SKS. Also these types of rear sight's are made for specific rifles so they are not that interchangeable but hell it so looks nice and trust me you are going to love the ability to change windage while shooting your irons