What is a 21 volt lithium ion battery?

【21 Volt Lithium Battery 】Battery voltage: 21v, capacity: 4000ah, type: lithium ion, made of 10 pcs quality lithium ion battery,can provide stable capacity and output. ★【Charger】Support 100-240v universal standard ac input voltage.1a power adapter,us plug,led indicator to easily see the charging situation.

How many lithium ion batteries do I Need?

1 Lithium Ion batteries required. ★ 【Compatible with More 】Our batteries are compatible with some major brands, for power tools bl1860b bl1850 bl1840 bl1850b-2 bl1845 bl1830 bl1820 bl1815 lxt-400 series please feel free to contact us for more model information.

How does a lithium ion battery work?

Overcharge and over-discharge protection to increase the life of the battery. The Lithium-Ion battery charges faster and works longer than standard lithium-ion batteries, giving you and your cordless tools unmatched performance and productivity to take on the most demanding applications.