Headphones on the go, with no strings attached.
The attraction to wireless headphones is apparent. They offer a freedom of movement and activity that exceeds even the most portable corded headset. Wireless is especially effective for sending audio from large non-portable equipment such as a home theater system, TV or stereo. The ability to sit on the couch and listen to your audio system is easier without having a cord draped across the living room. With wireless headphones you can even walk around the house and never get the cords tangled.
Wireless headphones have a transmitter close to the audio source that will send signals to the headset which acts as a receiver. The transmitter/receiver communication can use a variety of standards and frequencies, although the range can vary. Generally speaking the higher the frequency used by the wireless headphones the less affected by interference they'll be, giving a cleaner static free sound. A decent quality set of wireless headphones shouldn't have static until you start to enter the transmitters range limit. Sometimes this can be as short as 30 feet or even less, while others like Sony's MDR-RF960RK 900 MHz RF Wireless Headphones have a transmission range of 150 feet.
When making the decision of what kind of range you'll need it helps to be a little skeptical of the printed range. These are usually rated in optimal environments not the real world of the average household where other wireless devices produce interference and environmental obstacles like walls, doors and floors are found. Other technologies are used in the transmission of headphones like Sony's MDR-IF630RK that use infrared to send the audio signal to the headset. These wireless headphones also offer noise reduction. Logitech's wireless headphones are lightweight and use Bluetooth 1.2 to produce a stronger signal with less interference than Bluetooth 1.1 wireless headphones offered by other manufacturers.
Most wireless headphones are battery operated so it's important to keep them well charged or the signal reception can be affected. The best choice for longevity is a set of headphones with removable batteries which are the standard except in the tiniest lightweight portable headsets. Some tiny headsets will use non-removable rechargeable batteries with no way to replace them. But despite the added mobility of wireless headphones the most important function they serve is to reproduce sound. No matter what range or technology the headset claims to offer, it's important to audition the headphones as you would any other non-wireless headphones. Comfortable fit, quality sound, ability to reproduce bass and clear detailed mids are the primary things to listen for when auditioning your wireless headphone.