Original old 1908 Patent Crosby steam gauge with Providence Engineering Works on the face.  It is a Receiver gauge with graduations to 30 pounds of vacuum and 50 pounds of pressure.  The body and face are nickel-plated solid brass.  It is 11 3/4 inches outside diameter at the front and 12 1/2 inches at the back.  There is a copper piece protruding about 3/4 from the back.  It has 1/2-inch female threading.  The gauge is in working order, but it will need calibration.  There is tarnish and wear.