Sports beanie keeps user cool & dry while delivering crisp, clear soundWicking fabric beanie to pull away moisture during activityIncorporates AERIAL7?s Sound Disk speakersTunnel inside beanie allows for speakers to be adjusted or slid partially or completely off the earIn-line microphone for use with mobile phonesUltra-slim speakerDriver dia: 35mmFreq resp: 20 Hz?20 kHzInput plug dia: 3.5mmBlue