Power up your devices reliably with these innovative 9V rechargeable lithium-ion batteries. Boasting a substantial 5400mWh capacity and steady voltage output, these batteries keep your devices running longer than traditional options. The built-in USB charging port eliminates the need for separate chargers - simply connect using a USB cable and monitor the charging progress through the LED indicator. Thanks to the advanced iQuick charging technology, these batteries reach full charge in just 2 hours with a 5V/2A input. Free from memory effect issues, these batteries maintain consistent performance through multiple charging cycles. They're perfectly suited for a wide range of applications including walkie-talkies, microphones, musical instruments, toys, flashlights, and various portable electronics. Note that like all 9V lithium-ion rechargeable batteries, these operate at 8.2V-8.4V when fully charged. The high-density energy storage and superior power efficiency make these batteries a practical choice for your portable power needs.