The photo he posted with a 35/3.5 Nikkor mounted on the Nikon F is very misleading. I emailed the seller as to whether the Nikkor focused properly and this was his reply:
Hello there, NO NO NO, This adapter allows to mount a
Leica style M39 to ANY Nikon F body mounted devise, It will
not allow to focus in infinity, I`m showing a RF lens as an
example,
Some lens will focus, I have used a Nikon EL-Nikkor 63mm
on a nikon D2, and was able to focus to infinity , just by
turning the lens in the mount ,
Please again understand this adapter allows to mount a
lens only, NO WARRANTY ON HOW SOMEONE WHOULD LIKE
TO USE IT