LR721 battery: equivalents & specs
The LR721 is a 1.5 volt alkaline button cell, 7.9 mm across and 2.1 mm tall, carrying the alternate codes AG11 and LR58. The same-size silver-oxide cell is the SR721, sold at watch counters as the 362 (low drain) or 361 (high drain).
Same battery, other names
Every code below is the exact same cell as LR721. Any of them will fit and work identically.
Compatible replacements
- SR721SW / 362: Silver-oxide equivalent (362 low drain, 361 high drain), the standard watch cell in this size.
Buying and replacement notes
The AG11 is among the less common AG sizes in retail packs, so if a device takes it you may find the silver-oxide 362 easier to buy, and it is the better cell anyway. Watch repairers stock the 362 as a staple size for mid-size quartz movements. As with all alkaline button cells, do not leave a dead AG11 sitting in a device; they leak more readily than silver oxide once exhausted.
Commonly used in
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⚠️ Keep away from children. Swallowed button batteries, especially 20 mm lithium coins, cause severe injury within hours. If a child swallows one, call the 24/7 National Battery Ingestion Hotline (US) at 800-498-8666 or poison control at 800-222-1222 immediately. What every parent should know.