Helmets ID

[davejb]

You will find the size markings generally on the left hand side of the inner skirt just below the chin strap post or with the case of some M42s at the rear skirt

[mich]

you right,
I found it in 2 of them

[davejb]

I can see the first one is a Quist 66, its possible the second is also a Quist ,possibly a 62, try the chalk test, take a piece of chalk, draw over the markings then wipe the excess away, it should help to give a clear mark, for your information the other numbers at the rear are lot no/s ie production no/s