It's a What?

I left my computer glasses at work so this will be a quick blip.  At the weekend I found this light meter in a little leather suitcase belonging to my parents.  I know nothing about light meters.  It looks complicated.  I probably have it up side down.  What do I do with items like this or thirty years of birthday cards?  We have a friend who wants to get back to how he was at 18 when he could fit all his possessions in his Rover 90 car.  That is too minimalist for me but I do have to start to declutter.  I wonder if someone does that as a job.  They come and tell you what to do with all your paper backs from the 70's.