Bought for the PX200 they earpads. The old ones were but very worn. Cost point about half as in the original Sennheiser spare parts. Although I had never done an exchange and no instructions came with, the installation went relatively unproblematic. Have the impression that they are a little harder than the original, but that does not necessarily have to be negative.
Addendum 27.01.2014: The pads are actually a little harder than the originals and sit not by quite as comfortable. For the price but that is fine. Those who value a perfect fit, all we have yet to twice as expensive original.