The JBL Tune 520BT headphones stream powerful JBL Pure Bass sound thanks to the latest 5.3 BT technology. Easy to use, these headphones provide up to 57 hours of pure pleasure and an extra 3 hours of battery with just 5 minutes of charge. Download the free JBL Headphones App and customize your sound through the EQ, while Voice Prompts guide you through the headphones features. Manage calls, sound and volume from the earcup, thanks to the convenient button control. If a call comes in while you are watching a video on another device, the JBL Tune 520BT seamlessly switches to your mobile device, so you never miss a call. Lightweight and comfortable even after hours of listening, the JBL Tune 520BT headphones fold flat in your backpack to follow you everywhere.SpecsGeneral SpecificationsDriver size (mm)33ActivityLeisureNumber of Microphones1Audio SpecificationsDriver sensitivity at 1kHz/1mW (dB)102Impedance (ohms)30Dynamic frequency response range (Hz)20 Hz 20 kHz