Boomphones Phantom Headphones with Boombox - Black/Pink The first-ever headphones that can transform into a boombox with just the push of a button. Designed with four speakers: two on the inside, and two on the outside. Make and answer phone calls, whether listening privately or, with the push of a button, switching to speakerphone. Built-in lithium battery easily recharges through a mini-USB, providing a full 10 hours of internal use and 5 hours of external use. LED lights are used to indicate which mode is in action. The white LED indicates your Boomphones are internally amplified, and ready to ROCK. The red LED indicates your Boomphones are in Boombox Mode, and ready to BLAST. Turn your Boomphones into a portable amp. Plug into your computer, electric guitar, keyboard, beat machine, etc.