These JBL Tune 520BT Headphones allows for powerful sound without any wires for up to 57 hours on a single charge. It can provide up to 3 hours of playback after a 5-minute charge! This comfortable model with JBL Pure Bass technology guarantees high sound quality at any time. Thanks to the folding design, the model easily fits into any backpack or bag. If you receive a call while you are watching a video on another device, the JBL Tune 520BT will automatically switch to your mobile device.