Krankz Wireless Bluetooth On-Ear Headphones (Black) Incredibly clear and powerful sound. HD speakers, making every note sound crisp and clear. Built-in microphone and automatic call notification for easily switching between music audio and phone calls when paired to your smart phone. Easy playback. Instead of digging around for your music player or phone when you want to change a song, or answer a call, use the intuitive headset controls on your ear cup for managing your listening experience. High efficiency rechargeable battery delivers over 44 hours of battery life. Longer battery life means you can listen to your music and talk for hours without interruption. To recharge your headphones, just plug them into any computer USB port or USB power cube.