Bluetooth Earphones V4.1, Blackzebra Wireless Stereo Sports Headphones for Running Gym Exercise Sweatproof Headsets for iPhone iPad Android Smartphones (HP-S1S Upgrade) Upgrade version: Compaired to HP-S1, HP-S1S equipped with efficient Neodymium magnet speakers, Providing perfect High-quality sound. The latest Bluetooth V4.1: Stable signal transmission with electronic noise cancelling will never disconnect during the sports. Ergnomic design: Completely fit for your ear, enjoy a comfort journey of music. Sports style: For durable design with sweatproof meterial, the earphone will not slip out of your ears even with a strong shake. Multi-function: Pairing with two devices; Pair the last device automatically; Built-in microphone; Battery level indicator with iOS devices.