This is an Olympus Pen EE-S2 which I believe was introduced around 1968. This particular sample was acquired on eBay for $17 plus shipping. It exhibited the one problem that I have found to be most common in the Pen E series, the aperture did not function. Features of this camera are selenium cell auto exposure and flash settings where you select the aperture. Two shutter speeds, 1/40 and 1/200. Zone focus. Half frame 18 x 24 mm format. When the camera is functioning normally, you will observe that the aperture opens to its appropriate setting as you press the shutter release button. In the automatic setting, if there is not enough light, a red flag should rise in the viewfinder and the shutter release should lock. If you do not observe this behavior, don?t assume that the meter is dead. The flaw is usually mechanical in nature. Remove the top cover and you can observe the meters needle (red circle) move as you point the selenium cell toward a light source. As you press the shutter release, the needle is trapped between a static plate and two moving jaws or pinchers. I?ve hear this being referred to as ?trap-needle metering?. If you see the needle move, your selenium cell is good.