Exposure meter, model #625, made for all rollfilm cameras except the J33 and J66. The calibrations are read directly in EV numbers only. It was made for Polaroid by Gossen. It was also supplied with an accessory foot so it could be mounted on older models. For the latter, an extra stick-on exposure number scale was added so the calibrations could be adjusted in the old Polaroid "Light Value" numbers. (See the left flyer in the picture.)
In its original packaging.
This accessory is described in the very useful Land List
website.