Important Note: To comply with safety regulations for storage and shipping, this headset is shipped in a battery-depleted state. For the best initial experience, please fully charge the headset before first use. Dual microphone design, clear calls even in noisy environments Works on all Bluetooth enabled devices, such as smartphones, laptops, tablets, MP3 players and other streaming devices. The earphones come with a built-in remote control, allowing you to adjust volume, control music and video playback, and answer or end calls with just one touch. The speakers inside Earbuds have been engineered to maximize sound output and minimize sound loss, which means you get high-quality audio.