Altimeter, Sensitive, Type C-12, 50,000 ft, US Army Air Force WWII (2) Battle where the master switch is

where the master switch is a flat toggle instead of a push/pull switch as designed in this B-6

and Civil Date Function

long before the war

and the interior side of the glass requires cleaning

which leads to a conclusion of a misprint

Altimeter, Sensitive, Type C-12, 50,000 ft, US Army Air Force WWII (2) Battle where the master switch isHere is an early WWII era Sensitive Altimeter, Air Corps US Army Type C 12, made by Kollsman, part number 671 BK 010. The C 12 Altimeter was used across all aircraft of the Air Corps US Army, including heavy bombers B 17 and B 24, medium bombers, B 25 and B 26, Fighters P 38, P 39, P 40, P 47, and P 51, and transports C 46 and C 47, according to the Maintenance Interchangeability Chart dated Dec 1943. It has a serial number prefix AF 43, evidence of a