This is the somewhat obscure Leitz New York SOOGZ, which adapts their E39 filters to their A36 filters. This allows the use of comparatively modern Leica-fit E39 filters to older lenses such as the Elmar 5cm F3.5 (and some others). This version was made by Leitz, New York, which makes it additionally valuable as a collectible. The condition looks good, but I haven't used it. My asking price, compared to what they often sell for, is actually low!
Price: $100 plus shipping
Price: $100 plus shipping