Tachometer, US Navy Mark V, Kollsman 621KN-04, 88-I-2500, SBD, TBM, F6F, PBY Seagull and another full rotation to

and another full rotation to 4000 RPM

This is a Beam Compass Indicator

Weston model 425

but is in exceptional condition for its age

Also see photo of the switch installation in the B-29 from its Flight Manual dated 1943

Tachometer, US Navy Mark V, Kollsman 621KN-04, 88-I-2500, SBD, TBM, F6F, PBY Seagull and another full rotation toHere is a very nice example of the US Navy Mark V WWII post WWII era electric tachometer, made by Kollsman (part number 621KN 04), as used in aircraft of the US Navy such as the SBD Dauntless Dive Bomber, the TBM Avenger Torpedo Bomber, the F6F Hellcat Fighter, and the PBY5A Catalina Seaplane (which used 2). (See photos of the SBD and TBM instrument panels from their WWII era flight manuals showing the instrument location). It is in fine condition