Manifold Pressure, Dual, Set for 4-Engine Aircraft, AN5770-2, D-11 Vickers The formation stick was used

The formation stick was used to quickly maneuver the aircraft with minimum physical effort while the C-1 Autopilot was on and the aircraft was assuming

and D (Dull) are displayed on the inner ring

This is Mach Speed Indicator

Air Corps US Army Type C-13 (also AN-5760-1)

Manifold Pressure, Dual, Set for 4-Engine Aircraft, AN5770-2, D-11 Vickers The formation stick was usedHere is a set of WWII era AN5770 2 (formerly D 11) Dual Manifold Pressure Indicators, as used in four engine of the US Army Air Force such as bombers B 17, B 24, and B 29 and transport C 54. The indicator marked for engines 1 & 2 was made by Ranco with a 1943 manufacturing serial number prefix. The indicator marked for engines 3 & 4 was made by American Meter with a 1944 manufacturing serial number prefix. These were also used in twin engine aircraft