Turn and Bank Indicator Pioneer Type C635C-84

This pneumatic Turn and Bank Indicator, Type C635C-84, is very similar to early WWII-era Turn and Bank Indicators also made by Pioneer/Bendix as appeared in military aircraft of the US Army Air Corps and US Navy.  However, there does not appear to be any markings of either service branch, nor evidence of its year of manufacture.

The design of the mounts of aircraft instruments evolved during early WWII from the dog-ear-style as seen on this instrument to a more robust integral design that was less vulnerable to breaking on a hard landing, as was the dog-ear-style.  Hence our guess that this is a late pre-WWII era indicator (e.g. late 1930's) used in commercial or civilian aircraft.  

It is in good condition given its apparent age. The fluid in the inclinometer is intact as is the metal ball and the glass lens.  Measures 3.25 inches diameter and ~5 inches long.