IK Multimedia iLoud 40W Portable Personal Speaker 40W RMS  twice as loud as comparably-sized speakers 50 Hz to 20kHz frequency range with bass reflex port for superior low-end performance Two-way 2x3 neodymium tweeters for crisp clear high frequencies Advanced digital crossovers for incredible midrange detail. Battery powered with up to 10 hours listening time iRig circuit for use as a guitar/mic interface for iPhone and iPad