Concerning this item [JBL Pure Bass Sound] - The JBL Tune 520BT makes use of the well-known JBL Pure Bass sound, which is powered by the same technology found in the world's most renowned venues. [Technology of Wireless Bluetooth 5.3] With the aid of the newest Bluetooth technology, you can wirelessly stream high-quality sound from your smartphone without the mess of messy cords. [Perfect the Listening Experience] Get the free JBL Headphones App to adjust the EQ to your preferred sound. The JBL Tune 520BT makes use of the well-known JBL Pure Bass sound, which is powered by the same technology found in the world's most renowned venues. [Speed Charge and Up to 57H Battery Life (5min = 3H)] Listen wirelessly for up to 57 hours for extended enjoyment, and recharge the battery in as little as