The CV979 is a thermal delay switch based on the commercial DLS10. The specified delay time is between 60 and 120 Seconds.
The fixed electrode is on the left. On the extreme right of the picture can be seen the heater wires.
The two coiled heaters are connected in parallel. The delay is given by the time it takes for the heater to so heat the bi-metallic strip that it bends to touch the fixed electrode.
The balloon envelope is 45 mm in diameter and, excluding the B4 base pins, is 98 mm tall.
