BB389, 1432, H1155, K756, ALLDRY 1, Alldry No.1
Socket on top.
The 8 “D” size (U2) cells are in parallel in two vertical stacks of four cells. Using 8 cells in parallel gives somewhat more capacity than 8x as the internal resistance of the pack is 1/8th, but capacity is based on 1V end point for 1.4V filament valves (tubes) and 250mA nominal drain.
Use 4 off Alkaline D Cells in parallel (check that same date code, unused and condition good) for about the same or slightly more capacity.