[LargeFormat] Flash bulb batteries

[philip Lambert]

At a camera fair today,  amongst all the sad unusable relics and grossly
overpriced modern stuff I bought forty assorted blue flashbulbs, AG1, Pf1B
and flashcubes with two tiny AG1 flashguns for seven pounds ($10) because at
100 ISO the aperture indicated at 10 feet is f16, compared with f5.6 on my
small electronic flash. Some of the bulbs look purely experimental but
others look as new. The flashguns use tiny 15volt batteries.  Does anybody
have a source for these batteries please?. If I can get the guns working
they might serve for illuminating interiors, possibly firing the second
flash off a slave device. Thanks. Philip.