Course and Speed Calculator, RAF Mk II, 1928 (FLITEC171)
This is a British flight computer developed between the world wars and used by RAF aviators and navigators during WWII. In its original wooden, felt-lined case.
According to collector George Fulford's notes:
What is interesting about this is that it still has its original bruised pencil housed inside of the 'airspeed m.p.h.' hole. You can still read the "HB 1. TOUGH. WOLFFS SELECTED SPANISH GRAPHITE MA...' Five inches remain and the lead has been cut with a penknife rather than a pencil sharpener, which make me confident it was used operationally.
I've always been historically fond of this nice heavy piece of engineering, but it was inevitable that the classic E-6B of all these years would replace it.