Just be glad it isn't a G.O.W. in a Philco-Ford Sierra 135b, 128A Frequency
Selective voltmeter.

They used 2 as lock indicator lamps on the tuning dials. 1 for mhz band. If
either one burnt out the Calibration fails. and accurate (government spec's
accuracy) signal voltage or dbm measurements. And then you had to submit the
thing to calibration for repair and re-cal.

Much easier to have a few G-o-W bulbs on hand and pop the cap off and replace
it.

RHB