Features: Multiple Playback Modes: NIA NX100 headphone supports playing music via BT connection, TF card, FM radio and 3.5mm audio cable. Ergonomic Design: Foldable and rotatable slow rebound protein earmuffs, easy for storage, and comfortable to wear for a long time. BT 4.2 Connection: Advanced BT 4.2 technology offers fast transmission speed and high-quality signal. Easy to connect with BT-enabled devices. Long Battery Life: 400mAh rechargeable lithium battery ensures about 12 hours of music or talking time. Recharged via the included Micro USB port. Hands-free with Mic: Built-in microphone enables hands-free calls to set free your hands when doing sports and delivers clear and real talking sound. Great Sound Effect: 40mm large size drive unit, excellent titanium-plated diaphragm bring shocking bass, midrange fullness, and clear treble.