【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.【21 Volt Lithium Battery 】Battery voltage: 21v, capacity: 4000ah, type: lithium ion, made of 10 pcs quality lithium ion battery,4 LED fuel gauge power display,battery light won't light up unless you will press the battery button, in order to reduce battery.【Charger】Support 100-240v universal standard ac input voltage. 1a power adapter,us plug,led indicator to easily see the charging situation.【Multi-Protect Safety System】This battery is equipped with overload protection, overheat protection & over-discharge protection.【Note on Battery】In order to protect the battery, please do not charge more than 6 hours.Note: Please Fully charge the battery before its first use. Please do not charge the battery for overnight since it will badly damage the battery life.【WE’VE GOT YOU COVERED】 Any Non-human Damage Or Any Reason You Are Not Completely Satisfied With Our Product, We Will Immediately Provide You A Full Refund ( Or Replace Your Item).【Great Gift】For Dad, Mom, Husband, Friends And Family. Product Description A Great Gift Idea For Dad, Mom, Husband, Friends And Family, Suitable For Everyone Who Needs It, Whether You Are A Professional Or An Average Person. Any Non-human Damage Or Any Reason You Are Not Completely Satisfied With Our Product, We Will Immediately Provide You Replace Your Item. Type: 4.0AH Battery Rated Voltage: 21V Power Input: 400W Charger Input: 110V, 50Hz-60Hz Parameters Display 4 led electric quantity display Number of Batteries: 1 Battery Weight : 20 OZ Cells Per Batter: 10 Type: Battery power adapter Material: ABS Plug type: US Input voltage: 100-240V 50HZ/60HZ Interface: about 5.5*2.5mm/0.2*0.1in Output current: 1A Weight: 9 OZ How to install battery Step 1: Hold the machine firmly with one hand. Push down the battery unlock button located on the rear side of the battery with the other hand.Step 2: Keep pushing the unlock button down and slide the battery backward out of the machine.Step 3: You made it. Note： 1. Do not try to open the battery. 2. Protect the battery against continuous intense sunlight, fire, water, and moisture. 3. Do not damage the battery with sharp objects. 4. Do not discard this product at will. 5. Overcharging the device will reduce the life of the battery, unplug it from the charger in time to avoid overcharging. 6. If the battery does not last 10 minutes, it may be caused by overheating. Please wait for 5 minutes for the battery to cool down. Please read the following notes on battery maintenance carefullyAfter receiving the product, please fully charge the battery before using it.In order to protect the battery, please do not charge the battery for a long time. The best time to charge is not more than 6 hours.Please do not charge the battery all night, it will seriously damage the battery life.Always remove battery pack from your tool when you are assembling parts,making adjustments,cleaning,or when not being used for an extended time.Do not leave the battery dormant for long periods of time. We recommend using the battery at least once every two to three weeks. Battery 4.0Ah battery 4.0Ah battery 2.0Ah battery Battery Power Ddapter Electric Quantity Display