I believe this is for a Military Aircraft – It says 2 speed synchro transmitter by Kollsman Instrument Corporation. Definitely older piece – Large weighs over 6lb – NOTE the thumbscrew on the right side seems to be stripped.. The adjuster on the left works nicely. This item is in the category “Collectibles\Transportation\Aviation\Military Aircraft\Other Military Aircraft Items”. The seller is “montechristo13″ and is located in this country: US.