The JBL Tune 520BT headphones stream powerful JBL Pure Bass sound thanks to the latest 5.3 BT technology. These easy-to-use headphones have a battery life of up to 57 hours, plus an additional 3 hours with an additional charge of just 5 minutes. Download the free JBL Headphones app and adjust your sound via EQ, while voice prompts guide you through the headphones' functions. Manage calls, sound and earmuff volume with the convenient button control. If a call comes in while you're watching a video on another device, the JBL Tune 520BT switches seamlessly to your mobile, so you never miss a call. Light and comfortable, even after hours of listening, the JBL Tune 520BT headphones fold flat in your backpack so you can take them anywhere.