Altimeter, Mk XVIIA, Ref 6A/1538 0-35,000ft, British Royal Air Force C-121 The clock is wound by

The clock is wound by turning this red knob counterclockwise from its home position

It not only describes the weapons (guns

This Soviet/Russian aircraft instrument appears to be for setting an airspeed between 70-220 kilometers per hour

Here is a WW2-vintage Rate of Climb (Vertical Airspeed) Indicator

and protects the lens from dirt and oil

Altimeter, Mk XVIIA, Ref 6A/1538 0-35,000ft, British Royal Air Force C-121 The clock is wound byHere is a British Altimeter Mk XVIIA, Rf 6a 1538 as used in WW2 RAF bombers such as the Avro Lancaster, showing a maximum altitude of 35,000 ft. The altimeter has the marking of ICAN, the International Commission for Air Navigation. ICAN was an international governing body established on the basis of the ICAO relating to the regulation of aerial navigation and dealt exclusively with the regulation of international air navigation and in particular