Boost Pressure Indicator, MK IIIm, 6A/1581, British Royal Air Force, 1943 C-121

Boost Pressure Indicator, MK IIIm, 6A/1581, British Royal Air Force, 1943 C-121Here is a WW2 era Boost Pressure Gauge, 7 to 25 PSI, used to indicate the supercharger power being delivered to the engine when demanded. Used in Merlin powered RAF, RAAF, and RCAF aircraft. According to the RAAF 346 Types and Locations of Instruments in RAAF dated 1945, the 6A 1581 appeared in the DeHavilland Mosquito. This is New Old Stock in its original box dated 1943. Mint condition gauge.

The knob itself is missing

Measures 5

and fighters P-38 Lightning and P-61 Black Widow

or film spools

but I've sold 3 from this lot which are identical to this one including the label)

The knob and card are a bit sticky

It is in nice condition for its age

it is marked for the Inboard fuel tank

25 inches diameter by 3 inches deep

shows a (+) positive reading indicating the current is flowing to the battery (charge)

Gun Director Mk 34 was used in USN cruiser classes Baltimore

as appeared in the Co-Pilot's Panel on the post WW2-era Boeing B-50D Superfortress Very Heavy Bomber