Not sure what these were exactly used for but looks like little yellow optical cars. They do have a focal length of 35mm. The middle rectangle part is 30mm long by 20mm wide by 4.5mm thick. The side with 1 hump is 25mm long by 17mm wide by 6mm thick. The side with 2 humps each 15mm long by 9.5mm wide by 5mm thick. Most are individually wrapped in original box.
