SINGLE EAR HANGING DESIGN & LIGHTWEIGHT : The OPTA Painless ear hook weighing in at only 5 grams will free you from bore some wires! Its earhook type wireless earphone helps eliminate discomfort in your ears and minimize hearing damage. It is suitable for both left or right ear. BLUETOOTH 4.2+EDR : The OPTA Painless ear hook is easily compatible with smartphones and most Bluetooth devices .Also you can enjoy high-fidelity stereo music and clear conversation within a wireless range up to 10m/30ft. BATTERY LIFE : Built-in rechargeable Battery: 90mAh; standby time: up to 100 hours; play time: up to 6 hours;fully charging time: only 2.0 hours. NOISE CANCELLATION : The OPTA painless ear hook has a Built in HD Sensitive Microphone which enables you to have deeper, richer bass tones & hands-free calling. SPEAKER UNIT IS EXTERNAL: The loudspeaker is close to the ear but it is not inside the ear. It will help to listens to the surroundings at the same time lets you be aware of your external environment as well.