Vintage Weimar Lux light meter from East Germany (DDR) 1968, new in original box

This is a vintage WeimarLux exposure meter, displaying both DIN and ASA film speed settings. It was manufactured in the former East Germany in 1968. Per Google Lens AI, it uses a selenium sensor and does not require batteries, but I have no idea if that is correct, nor do I even know if it works. I do know it was purchased in East Berlin in 1969 and, to my knowledge, was never used. The little instruction booklet was removed from the box and, for some reason, stored separately, which unfortunately means it got a bit wrinkled. (see photos).