Designed initially for air travel comfort these headphones offer superb quality audio and a very effective electronic noise cancelling facility. Comfortable for extended wear Excellent Hi-fi sound quality Effective noise cancelling 40mm speaker system for full bass and bright, clear mids and highs Auto power-off after 10 mins without audio signal Patented full-ear surround Use 2 x AAA alkaline batteries -last about 70 hours. Supplied in a travel case and come with a 6.5mm / 3.5mm converter and airline seat plug audio adaptor The noise cancelling function is user-adjustable.