Sony MDR-NC500D is the world’s first noise-canceling headphones with noise digital signal processing with a newly developed high speed software engine DNC. The result is about 99% external noise is cut off. Daily sounds from air craft, trains and other vehicles is cut off to a very great extent when using the head phones. Sony MDR-NC500D is powered by a built –in lithium battery. Battery case using 2 × AA batteries is also available. The built in lithium battery lasts up to 16 hours while alkaline batteries up to 10hours. A Sony MDR-NC500D headphone weighs approximately 195g with battery and comes with aircraft and AC adaptor plug. The headphones will be available in Japan from April 21 for approximately 49,350 yen ($492).