Power pack PP3

The PP series are all layer cells, often 4  or 6 stack of exact type used in "Batrymax"/"Radio Batteries HT packs (typically 4 x stacks of 15 "biscuit" style cells). There never was a PP2.

Connection type: miniature version of PP9 style snap.

About 460mAH at 10mA load. End point about 6V

Equivalents:

• GEC BB23
• Vidor T6003
• Others: DT3, TR3, VT3 and many more

Alkaline version is usally 6 x AAAA type cells and never "layer type biscuits", about 590mAH rather than expected 900mAH due to the "wasted" space of 6 x cylindrical cells.
Rechargeable NiCd versions may be 6 button cells and thus only 7.2V nominal. Some rechargeable NiMH may be 7 cells, thus only 180mAH but 8.4V nominal. The 220mAH or higher are usually 6 cell.

This model was developed for "shirt pocket" BC transistor radios. Modern miniature Radios  tend to use 2 x AA cells (or 2 x AAA), which is about the same volume but about 1200mAH at low drain with ZnC or 2500mAH with Alkaline.

Still in widespread production from many makers and available "High Street" Retail mainly due to use in "Smoke Alarms" and mains Clock Radio "clock backup".

In questo link sono elencati 204 modelli, di cui 146 con immagini e 92 con schemi.
Elenco delle radio e altri apparecchi della Ever Ready Co. (GB) Ltd.; London