Airspeed Indicator, 420 Knots, RAF Mk 9F*
This is a WWII-era 420 knot Airspeed Indicator, Mark 9F*, as used in aircraft of the British RAF, such as the twin-engined Bristol Beaufighter.
Airspeed is indicated as the pointer travels clockwise from the 6 o'clock position from 40 to 250 knots on the inner scale in the first rotation, then to 420 knots along the outer scale.
Yellow paint was applied to the lower half of the dial rim at some point in the life of this indicator. Otherwise, it is in very good condition given its age. Measures 3.5 inches diameter and 1.5 inches deep.