Vivitar 35 selenium light- exposure meter.
Simple and accurate lightmeter which will never need batteries
Very easy to use. Set the film speed (eg: 21 DIN / 100 ASA), point the meter at the subject, turn the dial unti the circle coincides with the pointer and read off a suitable setting for your camera. (In the images, I have just measured the light outside on a bright, but sunless, day. EV is 18 and this equates to 1/125 second at f/8)
Hardly used.
Weight, including case:107g