Sony Premium Lightweight Wireless Noise Reduction Hi-Fi Stereo Headphones The Sony Premium Lightweight Wireless Headphone System is designed to transmit analog audio sources wirelessly to its headphones with a range of operation of up to 150-feet. The headphones feature a built-in rechargeable battery that can provide playback for up to 25-hours per charge. They are charged by connecting to the transmitter base station, and produce a full charge in 3.5 hours. The headphones also feature 40mm drivers and an adjustable headband designed to provide comfort for long listening sessions.Wireless HeadphonesThe Sony wireless headphone system transmits an uncompressed 900 MHz radio frequency signal to reduce unwanted interference while the real-time automatic channel tuning prevents signal degradationExtended comfortAdjustable soft padded headband and Over-Ear earpads designed to provide maximum comfort. Listen to music for hours and forget you even wear them40mm DriversThe large 40mm driver units with neodymium magnets deliver broad, balanced, and accurate sound for an exceptional wireless listening experienceWireless TechnologySony's Digital Headphones use radio frequency signals and have an expanded reception range (up to 150ft) that does not require keeping the headphones within line of sight of the transmitter. Perfect for use with your TV, Computer or Hi-Fi radioLong battery lifeThe headphones feature a built-in rechargeable battery that can provide playback for up to 25-hours per chargeFast chargingA 3.5 hour charge will produce a full charge of approximately 25 hours