It is used in the Vanity lights
of a 1975 Travco 270(as well as other 70's years and models of Travco).
I have spent three nights trying to find a bulb with no luck. No one has ever heard of it. The number on it is 1143KF but that number does not cross to what I have. An 1143 is a Bayonett style bulb and mine is an edison screw type, The 1143K bulb looks right but it is an E17 base(17mm).
Mine measures 15mm. No one has ever seen or heard of this bulb ???
Anyway I am hoping someone here has.
It is 12 volt.