Tachometer, Mk V, US Navy 88-I-2500 Pre-WW2 This example has the manual

This example has the manual back-up ring-and-bead sight affixed to its housing

was used across all aircraft of the US Army Air Force during WWII

or 800 cycles

The keying switch is stiff

This is a WWII Flight Checklist "Flugklarmeldetafel" recovered from the crash site of a Luftwaffe Junkers Ju-88 A-4 twin-engine Medium Bomber in Poland

Tachometer, Mk V, US Navy 88-I-2500 Pre-WW2 This example has the manualThis is an original WWII era electrical aircraft Tachometer, Mark V FSSC 88 I 2500, as used across aircraft of the US Navy, such as the SBD Dauntless Dive Bomber, TBM Avenger Torpedo Bomber, and F6F Hellcat Fighter. Pioneer Bendix part number 2222 IF2 A. Range 0 3500 RPM, with the pointer indicating RPM hundreds and the inset window at 9 o'clock indicating RPM thousands. This tachometer is in exceptional condition given its age. Measures 3. 25 inches