This is a Vintage Teeple Co. Type CH2 Pressure Regulator. I don't know what it was used for but the indicators move freely and are adjustable, possible Boiler Gauge or Steam Locomotive. The pictures are a substantial part of the description so please examine all the photos and contact me if you have any questions. We will be happy to save you shipping costs by picking this up at our shop. Thanks for looking 101921-RK-06