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Battery Information
Battery Details

The differences between LR and SR cells:

LR cells are Alkaline Manganese based and have a lower energy density or capacity and are 1.5volts.
SR cells are Silver Oxide based, have a higher energy density or capacity and are 1.55volts.
See the Notes page for more info.

Do not confuse with these other batteries listed as "5"
LR41.
Do not confuse with these other batteries listed as "42"
LR44 (RW42); 333 (42); AD42 (Alldry 42).
Do not confuse this "B" with the 1/2AA "B" battery.
Do not confuse this "1154M" with the LR44 "1154" battery.

The PX400 / MR42 cell was originally a 1.35 volts Mercury cell commonly used in cameras and some watches and is now banned because of toxicity and environmental fears.

There are 3 possible replacements for the Mercury types:

1. The equivalent Silver Oxide cell, the S400PX, at 1.55 volts.
2. The equivalent Zinc Air cell, the WeinCELL MRB400 or Z400PX at 1.35 volts.
3. The Accucell-1, developed to output the proper voltage to run watch movements exactly as would the original Mercury cell.

WeinCELLs are only suitable for cameras and light meters, they are not suitable for watches due to lack of air entering the watch.

Although the Accucell-1 uses Silver Oxide chemistry it also has built in voltage reduction to bring the voltage into specification. The Accucell-1 has a distinctive appearance with its plastic collar and brass voltage reducing circuit board (see picture).

The 387S has a distinctive appearance because it is the 394 Silver Oxide battery wearing a plastic collar designed to adapt it to the correct size (see bottom picture).

Equivalents:

05, 3, 5, 10L120, 10SL18, 12, 12UECD, 14, 180, 214, 218, 242, 280-05, 343, 344, 344-1, 350, 387, 387-1, 387S, 502, 509, 529, 549, 569, 604, 1116M, 1133SO, 1139S0, 1151M, 1154M, 28005, Accucell-1, B, CX42, D344, D350, E344, E387S, E350, E400, E400N, EPX400, H-B, HB, HG11, HS-B, KX400, LR42, M08, MR08, MR42, MR1136, MRB400, NP343, PM400R, PX400, R350/14, RM400, RM400R, RW36, RW51, RW51/W2, RW56, S10, S400PX, SG11, SR42, SR42L, SR1136, SR1136SW, T400N, V343, V344, V350, V387, V400PX, V529, W2, WH4, WH8, WS12, Z400PX,

Image not to scale.	Common Name.	Dimensions. Diameter × Thickness.	Chemical Composition.	Nominal Voltage.
Accucell-1 387S	LR42.	11.6 mm × 3.6 mm Contacts: Case and flat side Positive. Raised area Negative	Alkaline, Silver Oxide (Ag2O).	1.5 volts (100 mAh), 1.55 volts (105 mAh) (Ag2O), (1.35 volts Accucell-1 Mercury replacement).