These headphones work great. They're Sennheisers and you usually can't go wrong with this brand.The headphone reproduces the full range of sounds very clearly and without distortion, if set up properly (I'll get to that).I've been able to walk around my home without experiencing too much distortion. Within the same room as the transmitter, the sound is really clear and robust. It's great not being tethered to one location or having to deal with accidentally yanking the cord out when moving around.Also, unlike my other enclosed-type headphones, the design allow for air to circulate freely. So your ears won't become uncomfortable warm during use. These headphones are very comfortable.As far as specs, you can get a good assessment of the product from reading the Amazon description so I won't go into that.For portable devices with a headphone jack, you simply have to purchase a "2-RCA (female) to headphone jack (male 3.5mm plug) adapter". Make sure the adapter is a "stereo" adapter versus a "mono" adapter. They look exactly the same, so beware. These adapters are pretty inexpensive.I was a little concerned about getting wireless headphones because of all the negative reviews I've read regarding sound quality, interference, etc.Sound quality and hissing can be minimized if you set up properly. Here's a quick "What to do":Portable Players (i.e. CD, MP3, Walkman, etc):1) If the device comes with an output other than the headphone jack, use it. This other output (line-out) is usually a jack that delivers a constant, high (i.e. loud) signal. Regardless of your headphone volume level, this jack will output at a constant, strong, loud signal. These line-out jacks are usually found on the back of some CD players.2) If the device only comes with a headphone jack, set the volume to max or near max. This is the setup I'm using. These headphones were bought primarily to be use at work, so I can listen to my iPod wirelessly.NOTE!!! If you're connected to a dedicated home amp/receivers/etc... DO NOT crank the volume all the way up or even remotely close to it. (The line out on your home amp/receiver will transmit a strong, clear signal regardless of the volume setting, if you're connected to the receiver/amp's line-out)The volume should be set high ONLY for smaller, portable devices that output less power such as an MP3 player or handheld portable CD player. You've been warned;-)Why set the signal coming from your unit as high as possible? It significantly reduces the background noise, since the signal being transmitted is strong. You won't need to turn up the volume on your headset as high since the signal being transmitted is strong. Yes, your portable music player will use up power faster, but who cares? Use a power adapter for your device.If your signal wasn't strong, you would need to increase the headset volume which also increases the level of background hiss. Try it out. I would speculate that a lot of these reviews, which complain of unbearable hissing, are a result of their device's volume level being set low.Hope this info helps. Enjoy the headphones... They're pretty nice. 

Question: What do you think about headphone?
Answer: These headphones work great