This is an engraver's pneumatic air scribe hammer. It came from the estate of a hobbyist engraver who also had a complete Paragraver system. It comes with the box and air hose as shown. I tested this on a compressed air supply and the hammer strikes the anvil, releasing when the air pressure is stopped.
I do not have access to an oscillating air supply. I have disassembled and photographed all of the components for your review. Appears to me to be in excellent condition. The item "GRS Pneumatic Air Scribe Hammer Carver, Engraver's Tool, Chisel, High Speed" is in sale since Wednesday, December 14, 2016. This item is in the category "Jewelry & Watches\Jewelry Design & Repair\Jewelry Tools\Engraving Tools".
The seller is "shibumido" and is located in Acworth, Georgia. This item can be shipped to United States, to Canada, to United Kingdom, DK, RO, SK, BG, CZ, FI, HU, LV, LT, MT, EE, to Australia, GR, PT, CY, SI, to Japan, to China, SE, KR, ID, to Taiwan, TH, to Belgium, to France, to Hong Kong, to Ireland, to Netherlands, PL, to Spain, to Italy, to Germany, to Austria, RU, IL, to Mexico, to New Zealand, PH, SG, NO, SA, UA, AE, QA, KW, BH, HR, MY.