The SoundZ SZ900BT Bluetooth Headphones in Black are wireless and lightweight with a faux leather headband. They have a 3.5mm plug, and a 40mm driver unit and also have a phone call / microphone function.Key Features- Supports Bluetooth 3.0- Built in microphone for hands-free calling, with acoustic echo suppression- Built in micro SD card slot- Bluetooth distance: 10M- Built in rechargeable lithium-ion battery (3.7V, 300mAh)- Playback time: around 5 hours