65-105 mask for Linhof 6x9 Super Technika III

I bought an old Linhof Super Technika III (6x9) with 65 Angulon, and

105 Xenar. My brother bought me a 65-105 mask for the rangefinder, but

I'm unsure how to figure out how the mask works for 2 lenses (65 and

105). Can anyone help?

Thanks

David

I hope, that my english is good enough for an answer:

you can push and pull the rear part of the rangefinder (i. e. the lens, through which you look). If you pull it out completely, you have the position for 105 mm. If you pull it until the first stop, you have the frame for 90 mm and if you pull it completely in, you have the frame for 65 mm.

yours sincerely

Thomas