100 Hz to 20 kHz - TrueWireless Stereo - Battery Rechargeable - 1 PackExperience powerful bass in a travel-friendly size with the Wireless Cube Bluetooth Speaker. Featuring TWS Stereo Sound, this speaker can also be paired with a second speaker to provide even more sound with a 33' range. Designed for more than just music, the Cube Bluetooth Speaker features a built-in microphone for hands-free calling at the touch of a button. Equipped with a rechargeable battery, this compact speaker provides up to 5 hours of continuous playtime on a single charge. Convenient on/off button allows you to conserve battery life when not in use. Wireless Cube Bluetooth Speaker also includes a microSD card slot for MP3 playback and carrying strap.