Flap Position Indicator, Autosyn, PN 6019-30C-3-B-1248
This is a 1940-50's era Flap Position Indicator made by Pioneer/Bendix. It is an Autosyn indicator, a Bendix brand that used an electro-mechanical sensor at the flaps which communicated flap position to this indicator electronically. It has a service stamp dated June 1956.
Measures 3.25 in diameter and ~6 in deep.