With its 100m wireless range the sony mdr rf811rk wireless headphones black gives you freedom to roam while listening to your favourite music these headphones also have up to 13 hours of battery life together with a headband that is self adjusting for your listening comfort specifications up to gives you freedom to roam up to 13 hours of battery life self adjusting headband for listening comfort 40mm neodymium drivers for powerful balanced sound 20 20 000hz frequency range driver unit