TWS Stereo Sound – pair two speakers together. Powerful sound in a compact, travel-friendly speaker. Built-in microphone for hands-free calling. Rechargeable battery – up to 4 hours of continuous playtime on a single charge. Convenient carrying strap. On/Off button conserves battery life when not in use. Compatible with most Bluetooth-enabled devices. 1.57 x 1.57 x 1.69H in.