This is one of Otto Musica's "Resonant" shoulder rests, adjustable for size (4/4+3/4) and height with non-folding legs. It has a mild S-curve, similar to Kuhn, and is a lovely match for your rosewood fittings.
Like-new condition and comes with a velour bag. I'd prefer to trade for a new set of strings (e.g. Tonica, Dominant, Zyex, or similar) but will also sell outright for $30, which includes PayPal service and CONUS shipping.
Thanks for looking!