I bought my RS170 in august 2011 and after more than 2years the original earpads were getting disgusting to put on my head.
The earpads fit perfectly and the padding is almost as good as Sennheiser's original material. The only difference I notice is that there is a little bit less volume of padding but it doesn't bother at all and it's still lots better than wearing worn-out pads.
Installation is very easy and done in a few minutes. There's also some documents in the package to guide you to their installation video on the website if someone would have trouble with it.
I'm very glad I quickly grabbed these ones instead of trying to get in contact with Sennheiser. I'm sure I wouldn't have had them in my house after 2days for such a low price if I went to Sennheiser.
When ordering these pads my husband thought them rather. expensive. Found them a bit difficult to fit on the headphones .We are so happy we bought them they are so comfortable to wear and has improved the sound.