Polk Audio AM6617-A UltraFocus 6000i Noise Cancelling Headphone Ultra-high performance sound in a headphone, with focused details, full fidelity and deep bass.Connectivity Technology: Wired Battery-assisted active noise canceling technology eliminates the distractions of the outside world (AAA battery included) Polk's exclusive Optimized Active Tuning takes advantage of ANC technology to improve the overall performance dynamics of UltraFocus headphones, significantly raising the bar for headphone performance