We guess this is MIG 21 cockpit old type device measuring drop of pressure . It has two scales. In the blue zone is written "Vuisota" / "Height" , and "Perepad davleniy" / "Drop of pressure". It is part of MiG 21 and MiG23 aircrafts used at the beginning of ‘80s in the ex-communist countries of East Europe.
Size of the front part 6,5 cm / 2,6 inches ; length 8 cm / 3,2 inches
Item in good condition. Precious find for aircraft collectors!