MDR-RF4000K is the codename of the new cordless phones presented by Sony, which will become available for purchase next month in April 2010.

The headphones make use of a 40mm long-stroke diaphragm to provide good sound quality, and as you can see on the image the whole set – headphones, and charging dock – all look pretty stylish. The battery life can last 7 hours, but if you need more the alternative is a normal AAA battery which will provide a total of 10 hours of non-stop sound. a