Feature: 1. Fine quality plastics material case, with impact resistance and shockproof design, wear resistance and with fine durability. 2. Built-in integrated microchip with stable working performance, prevents overcharging and self-discharge, provides multiple protections and stable voltage circuit. 3. Temperature protecting, overtime protecting, overcharge protecting, overcurrent protecting, overpressure protecting, and with protective panels to protects the battery. 4. There are two different capacities of 5pcs lithium battery cores or 10pcs lithium battery cores for you to choose, you can choose according to your demands. 5. Built-in LED power indicator helps you get work done more easily, it\u0027s timely to recharge, help you monitor the battery charging status and check if the battery is in nice condition. Specification: This is a kind of fine quality 21V rechargeable lithium battery, there are two different capacities for you to choose, you can choose according to your demands. There are two different capacities of 5pcs lithium battery cores or 10pcs lithium battery cores for you to choose, you can choose according to your demands. Built-in LED power indicator helps you get work done more easily, it's timely to recharge, help you monitor the battery charging status and check if the battery is in nice condition. Features: Fine quality plastics material case, with impact resistance and shockproof design, wear resistance and with fine durability. Built-in integrated microchip with stable working performance, prevents overcharging and self-discharge, provides multiple protections and stable voltage circuit. Temperature protecting, overtime protecting, overcharge protecting, overcurrent protecting, overpressure protecting, and with protective panels to protects the battery. There are two different capacities of 5pcs lithium battery cores or 10pcs lithium battery cores for you to choose, you can choose according to your demands. Built-in LED power indicator helps you get work done more easily, it's timely to recharge, help you monitor the battery charging status and check if the battery is in nice condition. Specifications: Name: 21V Replacement Battery Nominal voltage: 21V Battery type: 5pcs * 1500mAh lithium battery cores type, 10pcs * 1500mAh lithium battery cores type (optional) Item size: 5pcs lithium battery cores type: 120 * 76 * 50mm / 4.72 * 2.99 * 1.97in 10pcs lithium battery cores type: 120 * 77 * 70mm / 4.72 * 3.03 * 2.76in Power adapter: 87 * 50 * 69mm / 3.43 * 1.97 * 2.72in Item weight: 5pcs lithium battery cores type + adapter: 388g / 0.86lb 10pcs lithium battery cores type + adapter: 634g / 1.40lb Package size: 160 * 140 * 100mm / 6.30 * 5.51 * 3.94in Package weight: 5pcs lithium battery cores type: 410g / 0.90lb 10pcs lithium battery cores type: 645g / 1.42lb Packing List: 1 * Replacement Li-ion Battery 1 * Battery Adapter Package List: 1 * Replacement Li-ion Battery 1 * Battery Adapter