Sombrero 400909-40mAh High Capacity Rechargeable Battery: Long-lasting power
Give your smartwatch the juice it craves with this high-capacity rechargeable battery. Built to last (unlike your patience when your watch dies mid-workout), it keeps your gadget going longer, so you're not constantly hunting for a charger. Ideal for anyone who thinks 'low battery' is the ultimate buzzkill.
- Packs a 3.7V punch to keep your device running smoothly—no lag, no drama.
- With a 400909-40mAh capacity, it's like the Energizer Bunny for your wrist; it just keeps going.
- Fits more smartwatches than you can name, making it the universal donor of the tech world.
- 3.7V output
- Compatible with smartwatches
- 400909-40mAh capacity
- Long-lasting power
General specs
- Brand: Sombrero
- Model: 400909-40mAh
- Seller: Joom
- Voltage: 3.7V
- Capacity: 400909-40mAh
- Compatibility: Smartwatches
- First listed by seller: 5/23/25
If you are interested in more details, you can find full information on the seller's page.
Shipping options
United States
Comparison with similar products
| This item | Recommendations | |||||
|---|---|---|---|---|---|---|
Sombrero 400909-40mAh Long-lasting power
|
Rechargeable Battery for Smartwatches High capacity 380 mAh
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Lithium Polymer Battery 3.7V power output
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Lithium Polymer Battery 3.7V power output
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Smart Watch with Extended Battery Life 1000mAh battery with 100-day standby
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Smart Watch with Large Capacity Battery 710 mAh battery
|
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| Brand | Sombrero | CLOUD Phone Acc | Quhgahfa | Bunny House | Banlvs | LIGE |
| Model | 400909-40mAh | |||||
| Color | ||||||
| Rating |
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| Price | $7.30 | $9.89 | $4.93 | $5.50 | $59.99 | $35.19 |
| Seller | Joom | Joom | Joom | Joom | Amazon | Joom |
| Update | August 19, 2025 | August 18, 2025 | August 20, 2025 | August 20, 2025 | June 27, 2025 | August 22, 2025 |
| Voltage | 3.7V | 3.7V | 3.7V | |||
| Compatibility | Smartwatches | A1, DZ09, RYX-NX9, KSW-S6 | Smartwatches, Bluetooth headsets | Smartwatches, Bluetooth headsets | ||
High Capacity Rechargeable Battery
Zoé M.
Strasbourg
June 4, 2025
I bought this as a gift for my husband after his old battery kept dying mid-day—it was such a hassle, especially during workouts or concerts. This Sombrero battery solved that problem beautifully; it holds a charge for ages and keeps everything running smoothly. The only downside is the warmth, but it's a small trade-off for the convenience. Overall, it's a great solution that I'd recommend to anyone tired of constant charging.
- Pros: This battery is incredibly long-lasting, keeping my smartwatch powered through long days without needing a charge, which is perfect for my busy schedule. It fits my device well and delivers steady power with no interruptions, making it reliable for daily use.
- Cons: From what I feel, it gets a bit warm during extended use, which can be a minor annoyance, and while it works with many watches, it might not be a perfect fit for every model out there.