3.7V Li‑ion Battery 4000mAh | Lightweight Power

4.0Ah high-capacity Li-ion cells for longer working time (actual runtime varies by tool and workload). Built-in protection against over-charge, over-discharge, over-current, and temperature. Rugged housing, slide-on design, and low self-discharge for reliable storage.

Genuine replacement battery for Seesii cordless tools. Two options are available—21V 4.0Ah and 40V 4.0Ah.

Important: Choose the same voltage as your tool. 21V and 40V batteries are not interchangeable.

How to choose

• 21V 4.0Ah — for tools on the Seesii 21V platform (compact DIY tools such as impact wrenches, drills/drivers, mini chainsaws, inflators, etc.).
• 40V 4.0Ah — for tools on the Seesii 40V platform (higher-power lawn & garden tools such as M16 16 inch chainsaw etc.).

Specifications

1. 21V 4.0Ah
   Voltage: 21V (Use the original Seesii 21V charger only)
   Capacity: 4.0Ah (4000mAh)
   Chemistry: Lithium-ion
2. 40V 4.0Ah
   Voltage: 40V ( Use the original Seesii 40V charger only)
   Capacity: 4.0Ah (4000mAh)
   Chemistry: Lithium-ion

What’s in the box:  1 × Seesii battery (21V or 40V as selected)

Notes: Do not mix voltages or chargers. Check the label on your tool before ordering. Contact us if you’re unsure about compatibility.