Turn & Bank Indicator, Electric, US Navy Aircraft 1970 A-20 The date is set by

The date is set by depressing the small button just above the winding knob with a narrow tipped tool such as a paperclip

likely for a large multi-engine aircraft

made by Pioneer div of Bendix

and if the barrels should be depressed or elevated

indicating RPM for the rotor on the inner scale and rotor for the outer scale with a ratio of 9

Turn & Bank Indicator, Electric, US Navy Aircraft 1970 A-20 The date is set byThe electrically operated, gyroscopic Turn & Bank Indicator, Bendix part number 13907 2K A2 4, was used in aircraft of the US Navy during the 1960 70's. This indicator has a service label from the NARF (Naval Aircraft Rework Facility) Alameda CA, stamped Jan 1970. The floating ball indicator no longer contains damping fluid, so the ball glides but not in fluid. The dial markings are clear and the glass and case are intact. See photos. Measures 3. 25