YISCOR BS002RE Wireless Bluetooth Speaker, 2016 Upgraded Version, Bicycle Climbing Sports Outdoor 4.0 Stereo Speakers Waterproof Shockproof Portable Audio Sound, Making Calls & NFC Enabled, Red Up to 10hrs playback: it has a built-in 3600mah battery, which can last for up to 10 hours on a single charge The size may be small but the built in battery lasts for up to 8 hours on a single charge Make hands-free calls: use the built-in microphone with clear voice capture to make and answer calls on your phone Top CSR 4.0 Bluetooth chipset Bluetooth 4.0 technology and NFC enabled makes it connective to all Bluetooth and NFC enabled devices Waterproof and shockproof: when suddenly it is raining, you don't need to put the speaker into your bag in case it gets broken