Advanced Bluetooth 4.0 Sports Stereo Wireless Headphones Earbuds for iPhone 6/6 Plus 5s 5 Samsung HTC and All Smart Cellphones Advanced technology: Bluetooth 4.0; Compatible with most bluetooth enabled devices. Ergonomically in-ear designed to fit ear canals: comfortable and stable to wear for exercise. Low battery warning: a symphony of beeping will alert you when the battery is low. Also the usage status of battery will be displayed on IOS devices. 2-link design: connect your two bluetooth devices at the same time. Memorized auto pairing. Up to 10 meter effective range.