Now, Ive always wanted one of these and a fellow BBS member very kindly donated this one free of charge.

Now all I need to know is - 'What Is It?'

It came with a diopter sight. It fits in the non threaded side of a HW foresight unit but its too tight to fit in the threaded side. It has glass in the centre but it doesn't magnify.
I ask the font of knowledge in the 'Collectable' section - what is it?

http://smg.photobucket.com/user/Airs...l?sort=6&o=193

http://smg.photobucket.com/user/Airs...l?sort=6&o=196

http://smg.photobucket.com/user/Airs...l?sort=6&o=192

Thank you for any (sensible ) answers.

ATB
Ian