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Question: Can the rechargeable batteries by replaced by the consumer or are they sealed?
Document: I use these headphones on a treadmill. I tried several Bluetooth but these worked the best. the sound is great. I have them hooked to a tv. the earcup pads are easily removed and can be cleaned after each use. the batteries are rechargeable AA and can be replaced with other AA if you forget to recharge. there is one in each ear piece.
These earphones are excellant! I replaced a $100 sony wireless set with these and there is no comparison! They run on rechargeable AA batteries, so future replacement is no problem. I also bought a spare set of ear pads on ebay for $25 (shipped from Singapore), so I'm in it for the long haul.The sound is crystal clear and put my Bose speakers to shame.The range is good through my apartment, but does not include going down one floor to the laundry.
The batteries had to be replaced, they didn't have the recharge function, and they didn't last long.I had a set of Sony's, nothing but static, and they did not sound that good.
This was my wife's Christmas present and a bust!#1. Recharable batteries were dead after 4 hours and would not recharge.. I replaced to learn of more problems#2. Sound cable fitting does not insert properly into the Transmitter port. If inserted too far, it activates only the right earphone. By moving the fitting in and out there will be sound to both earphones...but loud on right and weak on left.#3.
The ear cups twist off and are made to be easily replaced when they wear out, the part number is supplied in the manual. This is a big improvement over the Sony.Right out of the box the base and headset are pre-matched so they are plug and play. You can add up to 4 headsets but each must be paired to the base. Instructions are clear and easy to follow on how to do that. Before first using them, you must charge the batteries for 16 hours.
These Headphones replaced Sennheiser RS 120. The Sennheiser RS 170 Headphones are Excellent Wireless Headphones. In comparison to the RS 120 , the  RS 170 are light years ahead. I was often irratated with the screeching "feedback" HISS while watching a movie  listening to music. If you bent over to get something the RS 120s will fall off my head onto the floor and sometime spilling the batteries onto the floor. The RS 120s do have better range than the  newer RS 170.
Overall these are excellent headphones that I highly recommend.BTW, this product comes with rechargeable batteries. I don't think that's in the product description.
It takes rechargeable AA batteries that last a long time and you just place the headphones on the sending unit to charge. Just a great product, and I got it for a great price.Sennheiser RS 170 Digital Wireless Headphone with Dynamic Bass and Surround Sound
Not really an issue for me, as I mainly use these to watch movies on TV in my den, and not disturb others in the house with high volumes.Set up took less time than it took to unpack everything. Install rechargeable batteries, plug into earphone outlet on TV, plug in power.........enjoy.
Pros:  Very good transmission between headphones and transmitter. Headphones are comfortable. Easy to set up. Rechargeable batteries last more than a few hours at high volume. Surround sound effect very good.Cons:  Makes an annoying hum at low volume but it's not detectable at high volumes. Expensive for what you get. Bass output much less than expected.
Answer: Yes you can replace the recargable batteries -- they are the same size as a AA Battery thus you can substitute regular AA Batteries till they run out.