Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: does it change channels and increase volume if you have any obstacule in front of the remote control?
Document: I have been using the Next Gen Remote Extender for over a month now and it works exactly as advertised. All of my home theater components are located in a closed cabinet and the device performs all the basic functions necessary to power on/off all the components, change channels, adjust/mute volume, change inputs for the tv, perform all the controls available on the Directv remote control. I have not had to change out the batteries so far. I would highly recommend it.
I purchased this item to facilitate control of my audio components (located inside my home) while listening to music through my outdoor speakers (in the back yard). This device works perfectly! I have an average-sized yard and my remote now works from every corner! No more going inside to adjust the volume, change a pre-loaded CD or select a different source. I love it!
Image sitting in the master bath and having the ability to change channels on the box in the bedroom (which is in a different room). NO, I don't work for these people (I wish I did) but they have another product family that can control many more units - I love this unit!! !
I have been an Audiophile for 40 years and this unit is the BEST product I have ever purchased (I also have the 433mhz unit). I use this unit to control the cable-box in the den which is hooked up to 3 other televisions that can be controlled by this unit. I can go down to the basement and change channels on the box upstairs in the den.
I was skeptical that this product was another take the poor man's money and run. But when I got it read thru the instructions and set it all up it worked like a charm. I have my stereo equipment behind a hardwood door and for years have had to have the darn thing open in order to use the remotes. After installation I could go into the next room, door closed and switch channels raise and lower volume - everything worked.
I do some light audio and video distribution throughout my house, but when I needed to control the volume for the outdoor speakers, I didn't have a great solution short of walking inside to adjust. While I could have extended my IR distribution system outdoors, it would have been a pain to do and also wouldn't have worked perfectly unless I pointed the remote directly at the IR Target.
Solution:  rf extender, just slap the battery style transmitter into the remote you want to use and position the infrared repeater (the flying saucer shaped device) in line of site to your unit(s) and away you go. I can now control my volume and voting controls on a single remote from about 50 feet away through a brick exterior wall on my pool patio. The remote I'm using is the programmable unit that comes with my pioneer elite receiver.
This unit worked for a while but stopped working after a day. Found out why. I had my Roku 2 box unplugged. Apparently the Roku 2 and this extender interfere once I plugged in the Roku box in and could never get it working after that. The LED worked on the front of unit but would not control my Dish Network box. Don't get this if you use Roku 2. Haven't tried it on Roku 1 yet.
Works without a problem . After trying wireless solutions (I'm talking to you IO Gear you suck) to get the cable box signal to the kitchen TeeVee after Comcast "improved my service" by making many previous channels unavailable , I finally gave up and bought a 35 foot HDMI cable, splitter  and ran it . With this unit you can control the cable box from the next room . Highly recommended.
All you do is replace one of the batteries in your remote with the included "battery", which is a combination rechargeable battery and radio transmitter. The "flying saucer" receiver plugs into a wall outlet and has an infrared "emitter" that you place in front of the Tivo. Your remote looks and works the same, but now works anywhere in the house.1/13/13 update-  Still very happy with unit. RF coverage is fine all over the house.
Answer: Yes it's using a wireless frequency and not infrared  which requires line of sight. You will be a will to change the channel from outside or on a different floor. The product works pretty well, and I would definitely by again if mine broke. The only issue I have had is getting the blaster to stay in front of the cable box. I rigged it with tape