Altimeter, Sensitive, 50,000 ft, Civilian Cessna

Here is a Sensitive Altimeter, similar to the WWII-era US Army Type C-12, made by Garwin PN 22-377. It is labeled for a Cessna aircraft and has a date stamp of April 1952. 

The Sensitive Altimeter displayed altitude using 3 pointers. The first and longest indicated 100's of feet, the second indicated 1000's of feet, and the third and smallest indicated 10,000's of feet. The knob is used to adjust the altimeter to the barometric pressure is displayed in the small window at the 3 o'clock position.  

It is in good condition given its age. The glass and case are intact, and the knob rotates, and the pointers move. Measures 3.25 inches diameter and ~4 inches deep.