Tachometer, Electric, Weston Type 545 Constellation and then in 1950's versions

and then in 1950's versions

so that the pointer may be set to zero at any existing atmospheric pressure between 28 and 30 inches of mercury

rocket detonation will be delayed after impact

25 inches diameter and ~4 inches long

Tachometer, Electric, Weston Type 545 Constellation and then in 1950's versionsHere is a WWII or pre WWII era electrical Tachometer measuring up to 2500 RPM, made by Weston. It is marked as being adjusted for series connection, so it may have been intended for a two seat trainer. It has two markers, yellow and red, along the dial scale that can be placed to indicate operating limits when installed. Measures 3. 25 inches diameter by ~2 inches deep.