Images of this key on board of WWII bomber Piaggio P.108
Page 18 of the manual: http://www.militarystory.org/piaggio-p-108-manuale-distruzione/
And on board of famous "Decennial Air Cruise" by Italo Balbo in 1933:
https://www.youtube.com/watch?v=U84GabH00VY (minute 10.24)
https://www.youtube.com/watch?v=tpmhmOHpI2c (minute 08.21)
