I'm very happy with the quality and performance of these spare parts that I bought to replace one of the adapters of my IE 100 Pro that I lost somewhere hoping that they would work well, and they did! None of the generic or different brand tips I tried worked correctly, they didn't give me the right fit for full bass response and good external noise isolation. I'm pretty sure it has to do with the length of the insertion tube, too short in all of them compared to the ones in Sennheiser's original parts.
