Hugh Hetherington Hearing Aid Museum
Hugh Hetherington Hearing Aid Museum

The Hearing Aid Museum

Hearing Aids of all types—Ear Trumpets, Carbon Hearing Aids, Vacuum Tube Hearing Aids, Transistor Hearing Aids, Body Hearing Aids, Eyeglass Hearing Aids and much more!

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Click on the "General Information" button (top button above) for an overview and general information on this category of hearing aid.

 

Hearing Aid Batteries

Mallory No. RM-401H Mercury Hearing Aid Battery

The Mallory No. RM-401H 1.4 volt mercury hearing aid battery was made by the Mallory Battery Company of Canada Limited probably between 1955 and 1965 or so.

The No. RM-401H mercury battery weighed 0.3 oz. (8 g) and measured 1⅛" by 7/16" in diameter (2.9 x 1.1 cm).

Note: the first series of pictures shows the Canadian version of the Mallory RM-401H, while the second series of pictures shows the British version of this same model of battery.

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Bottom view of the Mallory No. RM-401H mercury battery showing patent number 2542575.

 


 

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Front view of the Mallory No. RM-401H mercury battery showing the model number and voltage (bottom).

This battery, a size "N" (also referred to as size 401), was a popular size of battery for hearing aids used from the mid 1950s and still in use today.


 

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Side view of the Mallory No. RM-401H mercury battery showing where it was made.

It also shows 3 more Canadian patent numbers—452347, 486024 and 499194.


 

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Another side view of the Mallory RM-401H mercury battery showing the polarity. Interestingly enough, the positive terminal is on the bottom.

 


 

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Top view of the Mallory RM-401H mercury battery showing the negative terminal.

 

 

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Bottom view of the Mallory RM-401H mercury battery showing the positive terminal.

 

 

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This is the British version of the Mallory RM-401H mercury battery. The battery itself is exactly the same size, shape, etc. It is just the paper label that is different. This may be an earlier version of the above battery with a different (British) design.

 

 

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Front view of the British version of the Mallory RM-401H mercury battery. It reads, "Mallory, Mercury battery for hearing aids, RM-401H".

 

 

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Back view of the British version of the Mallory RM-401H mercury battery. It reads, "Mallory Batteries Ltd., Made in England, U.S. Pat 753090 Et al., Warning: battery ... (the rest is unclear).

 

 

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Left side view of the British version of the Mallory RM-401H mercury battery showing the positive terminal to the right (bottom of battery).

 

 

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Close-up view of the British version of the Mallory RM-401H mercury battery showing the model number (RM-401H).

 

 

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Top view of the British version of the Mallory RM-401H mercury battery showing the negative terminal.

 

 

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Bottom view of the British version of the Mallory RM-401H mercury battery showing the positive terminal. The inscription reads, "Pat. No. 753090 Et. Al."

 

 


 

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