old battery types.

[Andy Burns]

I remember AAs as HP7 or 'Penlight'

[Bob Eager]

I had a transistor radio that used TWO of them!

[tabbypurr]

There were 6v lantern packs with screw tops, might it be those you remember?

AAAs weren't much use until alkalines came along as they held so little energy.

NT

[mm0fmf]

#800 ISTR

[Bob Eager]

There still are. 4(L)R25X.

But I think the ones being remembered are the 918 (now 4(L)R25-2. They seems to have more rounded corners now (the old ones had a cardboard case).

[Max Demian]

Note that's two PP9s, not bell batteries.

[Max Demian]

The original penlight batteries often consisted of two cells in one paper sleeve, for the original pen light torches. If you just wanted one and the shop didn't have singles they would break the double one in half for you.

When they started the "high power" (zinc chloride) U12s they called them U7 rather than HP16 for some reason; later HP7.

[Bob Eager]

Yes, I should have trimmed more of the quoted paragraph. Still bloody big and heavy for a radio - as I found. But they did last ages. I had that radio for years and years.