Battery
1*AA
1AA
One AA battery inside the Walkman. Usually directly accessible on the outside, sometimes under the cassette.
2*AA
2AA
Two AA batteries inside the Walkman. Usually directly accessible on the outside, sometimes under the cassette.
4*AA
4AA
Four AA batteries inside, usually in some kind of holder. Sony also used it in the portable DAT range.
Sidecar 1*AA
EXT1AA
External compartment for 1*AA battery. Usually has a DC in jack to power the device, not to charge the battery
Sidecar 1*C
EXT1C
External compartment for 1*C (r14) battery.
Sidecar 2*AA
EXT2AA
External compartment for 2*AA batteries.
Sidecar 2*AAA
EXT2AAA
External compartment for 2*AAA batteries. Some Aiwa sidecars have 2V DC in jack.
Case 2*D
EXT2D
External compartment for 2*D batteries, like the Sony EBP-500
Gumstick
gumstick
Rechargeable rectangular battery (NiCd/NiMH)
dim.: 67x17x6.1 mm.
Voltage: 1.2 V
Gumstick 2V
gumstick2
Rechargeable rectangular battery (Lead-Acid), in different variants. Sometimes contacts are on top (logo side), sometimes on end.
dim.: 68x17x6 mm.
Voltage: 2 V