The STV75/15 is a small cold cathode voltage stabiliser. The ratings are most probably a maintaining voltage of 75 Volts at currents of up to 15 mA. The striking voltage is around 100 Volts. The connections are via a small bayonet base, exactly the same as would be used for a neon indicator.
The ceramic base to the cathode cup with the anode rod in the centre. The rod is sheathed in glass from the pinch to the cup.
The closed end of the cathode cup.
The wide glass tube envelope is 28 mm in diameter, and including the bayonet base is 73 mm tall.
