Sony UK this week introduced two new sets of headphones. The large, over-the-ear MDR-RF865RK set has a wireless range of up to 100 meters (nearly 330 feet) and sports built-in batteries that are recharged when the set is returned to its stand. They have 40mm drivers for solid audio performance and a built-in volume control. A full recharge takes 3.5 hours, with battery life rated at 25 hours.
