This is the rare black action finder for the F. It is a useful accessory that I am surprised is not more common. It allows you to see the whole frame from about four inches away and is only slightly dimmer than the eyelevel prism. This one works but is in rough condition. The mount is a little off, so on an F the rear pins lock but the front pin does not so it is slightly loose. The glass is slightly chipped at the top and botton. It is visible from a few inches away but not when you have your eye up to the glass. It does not get in the way of composition or focus.