Lumsing&reg; Portable NFC Bluetooth Speaker,Rechargeable Battery Powerful Sound Bass System for iPhone iPad MP3 Player Smartphones Laptop
I have no clue how big the battery is, but I've used it for two (8 hour) shifts, and it was still ready to go! It pairs easily through NFC, and while Bluetooth is only rated for 30ft, this went as far as 50ft. The sound quality is incredible, seeing as it has a subwoofer in the back. It's become an essential part of my work life, since I can also use it in phone calls. It has a microphone built in, so your device can remain in your pocket. I am surprised and pleased with how well this device works, and have