These new additions from Digital Silence are created by Wolfson who are renowned for producing some of the best sound chips in the audio industry. They have opted to make full use of their industry experience & create an impressive set of active noise cancelling headphones. Using technology that creates opposite sound frequencies, all external noise interference is eliminated. The in-line control allows for up to 30 hours of active noise cancellation. If you forget to charge your headphones you can still use the DA-101A as a passive noise isolating set of in-ear buds.