What is PX400 also called?

PX400 pack labels and aliases on this site include MRB400, Wein MRB400, S400PX. These are names for the same battery entity — not chemistry substitutes.

Is PX400 interchangeable with similar codes?

Related codes are not automatic equivalents. See Classic PX mercury cells and modern paths — match the code your device names.

Battery

PX400

1.35V mercury (legacy) button cell

PX400 was a 1.35-volt mercury cell. Mercury stock is obsolete. Wein MRB400 zinc-air is a common modern path. Not the same as PX625. See classic PX mercury replacements.

Chemistry: mercury_oxide_legacy
Voltage: 1.35 V
Diameter: —
Thickness: —
Used by: 0 devices

Common uses: Vintage meters / cameras

Common questions

What is a PX400 battery?: PX400 was a 1.35-volt mercury cell. Mercury stock is obsolete. Wein MRB400 zinc-air is a common modern path. Not the same as PX625. See classic PX mercury replacements.
What is PX400 also called?: PX400 pack labels and aliases on this site include MRB400, Wein MRB400, S400PX. These are names for the same battery entity — not chemistry substitutes.
Is PX400 interchangeable with similar codes?: Related codes are not automatic equivalents. See Classic PX mercury cells and modern paths — match the code your device names.

Other names

Genuine aliases and pack labels for this battery — not substitutes of a different chemistry.

MRB400 · Wein MRB400 · S400PX

Related codes

No related codes listed yet.

Devices using PX400

No devices listed for this battery yet.

Compare

Classic PX mercury cells and modern pathsCompare

Learn more

Testers & chargers

Optional tools that fit this cell type — only where the chemistry allows. Separate from the battery answer.

Amazon links may earn us a commission. They do not change the battery answer.

Battery tester
Quick good / low / dead check for household cells
Crude check only — does not measure capacity under realistic load.
How to test a battery Buy on Amazon
Battery storage / organiser
Keep spare cells sorted and prevent coin-cell shorts
Keep coin cells away from children.
Buy on Amazon

Buy links are optional and separate from the battery answer.

Need one?

Need a PX400?

Search Amazon for packs of this battery code.

Buy on Amazon Amazon UK

Buy links go to Amazon (Associates where tagged) or other affiliate programmes when available. They never change the battery answer.

Notes

Legacy 1.35V mercury cell. Obsolete. Wein MRB400 is a common zinc-air path. Not PX625.