A 377 is a silver oxide watch cell, 6.8 mm across and 2.6 mm thick, at 1.55 V. Renata prints it as SR626SW, and its high drain twin, the 376, as SR626W.
Printed on the flat side of a coin or button cell, or on the label of a larger battery.
What that code is
Type the code printed on the battery, such as 377, SR626SW, 376.
SR626SW, SR66 and the other names
Names for the 377 and 376 on makers’ sheets and cross references
Code
Chemistry
Where it’s printed
377
Silver oxide
Renata, Energizer, Varta (V377), Rayovac
SR626SW
Silver oxide
Renata’s 377 sheet; Energizer’s 377 page
376
Silver oxide
Renata, Energizer, Rayovac
SR626W
Silver oxide
Renata’s 376 sheet
SR66
Silver oxide
Renata’s 377 and 376 sheets; Energizer’s 377 page
D377, D376
Silver oxide
Renata’s list (Duracell)
SB-AW, 280-39, BA
Silver oxide
Renata’s list for its 377 (Seiko, Citizen, Timex)
LR626, 178
Alkaline
GP’s 178 page
AG4
Not placed
Not on Renata’s, Energizer’s or GP’s pages for this size
LR44, 35711.6 x 5.4LR1130, 38911.6 x 3.05LR41, 3927.9 x 3.6LR626, 3776.8 x 2.6
Ringed: the 6.8 x 2.6 mm cell, the smallest of these four. The 377 and the 376 are both this size.
Low drain 377, high drain 376
The two match in size and volts. Renata’s sheets call the 377 low drain, with 28 mAh, and the 376 high drain, with 27 mAh. Energizer’s silver oxide manual puts low drain cells in analog watches and high drain cells in LCD watches with a backlight, watches with alarms and calculators. Energizer lists its 377 as a replacement for “376/377”.
Casio watches that take it
Casio’s operation guides give an SR626SW for its watch modules 5125 and 5067: about 3 years on the 5125, and about 2 years on the 5067 with an hour of stopwatch use a day. The 5067 guide asks owners to leave battery replacement to the original retailer or an authorized Casio service center, and to fit only the type it specifies.
The alkaline LR626
GP sells an alkaline cell of the same 6.8 x 2.6 mm size as its 178, listed as LR626, at 1.5 V. GP gives no capacity for it. Casio’s guides above name the silver oxide SR626SW.
If a battery is swallowed
If a child or anyone else may have swallowed a coin or button battery, don’t delay: call the 24-hour National Battery Ingestion Hotline at 1-800-498-8666 or your poison center at 1-800-222-1222.
Common questions
Is SR626SW the same as 377?
Yes, by Renata: its 377 data sheet is headed 377 SR626SW (SR66), and Energizer lists SR626SW among the codes its 377 replaces.
What is an AG4 battery?
Renata's, Energizer's and GP's pages for this size don't name AG4. Look for 377, 376 or SR626SW on the pack or in the watch's manual.
Is LR626 the same as 377?
No. GP's LR626 is an alkaline cell of the 377's size. GP gives its 178 (LR626) as 1.5 V, and Renata gives the 377 as 1.55 V.
Codes, sizes and capacities come from Renata’s 377 and 376 data sheets and product pages, Energizer’s 377 page and silver oxide manual and GP’s 178 page; the watches from Casio’s operation guides; the swallowing line from the National Capital Poison Center. Checked against published data from Renata, Energizer, Casio, National Capital Poison Center and GP Batteries.
See all 9 sources
National Capital Poison Center (poison.org), Battery ingestion: National Battery Ingestion Hotline
Battery sizes come from battery makers' datasheets and device makers' own manuals and help pages. Check your device's manual or the old battery before you buy. If anyone may have swallowed a battery, call the National Battery Ingestion Hotline at 1-800-498-8666 or your poison center at 1-800-222-1222 straight away.
