Dual Boost/Manifold Pressure Gauge Ladedruckmesser Fl20556

This is an authentic WWII-era German Ladedruckmesser Fl20556, or Dual Boost/Manifold Pressure Gauge as used in twin-engine aircraft of the Luftwaffe such as the Heinkel He 219 Uhu night fighter, the Dornier Do 335 V Pfeil fighter, and Siebel Si 204 D transport. 

The instrument has two pointers: the pointer with the "R" is for the "Recht" or right engine, with the unmarked pointer for the left engine.  It has a pressure range of 0.6 to 1.8 ata (bar).  The outer rim has been painted red and white to denote a preferred operating range.  It correctly indicates resting atmospheric pressure at 1.0 bar.

It is in exceptional condition for its age. The Fl number is clearly indicated on its face and on the rear label.