Stay powered up for days- With up to 50 hours of battery life, you can listen to your favourite music without worrying about running out of charge. And, if your headphones battery is running low, a three-minute quick-charge can give you 1.5 hours of listening time. Crystal-clear calls- A built-in microphone provides you with hands-free calling, and it also works just as well for joining an online class or work meeting. Your sound, just how you like it- Tailor sound to your personal preference by choosing from a variety of pre-sets to match sound quality with the genre of music you're listening to. Or create and save your own pre-sets using the EQ Custom feature on the Sony Headphones Connect app. Multipoint connectivity- For total convenience, these Bluetooth headphones can be paired with two Bluetooth devices at the same time. So when a call comes in, your headphones know which device is ringing and connects to the right one automatically. Designed for all-day comfort- Not only is the design stylish, but It is also crafted with ease-of-use in mind. The lightweight build and swivel earcups gently slip on and off, while the adjustable headband, cushion and soft ear pads give you all-day comfort. Keep control with easy-to-use buttons- An easy-to-use selection of buttons help control your headphones, meaning you can play, stop or skip through your tracks and adjust the volume, all with a tap of your finger. Make your music more natural- When an original music source is compressed, it loses the high-frequency elements that add detail and richness to a track. Our Digital Sound Enhancement Engine DSEE faithfully restores these to produce high-quality sound that’s closer to the original recording. Take your music wherever you go- The compact, lightweight design and swivel earcups make the headphones the perfect companion for all of your travels Sustainability in mind- Our products are not only designed to be stylish, but with the environment in mind. Recycled plastic is used in the WH-CH520 headphones. Also, no plastic is included in the individual packaging. These headphones reflect the commitment from Sony to reducing the environmental impact of our products and practices.