bluetooth 5.1 and stereo sound quality:bluetooth headset bring you for a better music experience. compared to bluetooth 5.0, the 5.1 version features fast and stable signal transmission, clear sound quality without skips and distortion and low power consumption. at the same time, stereo headphones provides sound quality, the sound of immersive music scene surround sound, let you feel more realistic music charging case and led display: the charging box with built in battery can provide up to 40 hours of continuous music time. put the earbud into the charging box and will charge automatically. the charging box has an led display that lets you know when it is the charging time, bluetooth earbud are your great companion for sports and travel ip7 waterproof: sports earbud design, internal nano coating protects the headphones from heavy rains or sweat throughout intense exercises; just enjoy your time when running, jogging, riding, hiking, fitness, or in the gym. keep your headphones in good working order, even if you are drenched sweats after a grueling workout. ergonomic earhook design: with lightweight and ergonomic design, earhooks headset is a great combination of comfort and stability with ear hook and in ear fitting designed for strenuous workouts. lightweight and ergonomic design, customizable accessories with large, medium, and small size of gel eartips; soft silicon earhooks ensure comfortable and secure wear in even intense workout. easy to use: control buttons on the headphones so that you can play and pause music, adjust the volume, skip tracks, answer and end calls, and activate the voice control of your phone with one simple operation on the headphones. these headphones are compatible with most ios and android smartphones.