Altimeter, US Navy No 701, Tyco, 12,000FT, WWI-Post WW1 era
This is an Altimeter used in military aircraft of the US Navy either during or post WW1. This altimeter crudely measured altitude from 0-12,000 ft. By gripping the knurled rim of the faceplate and turning, the numerical scale rotates clockwise or counter-clockwise while the pointer remains stationary, to correct the altitude reading as required. May have been used in an airship of the US Navy. This looks very similar to the altimeter depicted in the JN-4D Curtiss Jenny cockpit at the US Naval Aviation Museum website.
It is in good condition given its age. Measures 6 inches diameter and ~2.5 inches deep.