I bought a set a year ago for a Bose Series X. I'm follically challenged, so I almost always fly with a hat. I also often use sunglasses. I've noticed both of these break the ear seal and significantly reduce the effectiveness of the headset. I talked with one of their sales people at Oshkosh who assured me these ear seals would help that. (He was bald too, so very credible.)
Oregon Aero has a stellar reputation, which is why I was so disappointed when I tried these. Simply put, they were awful! They appeared to be generic and didn't fit the headset very well. When I tried them in the plane not only did they fail to reduce the noise, they actually amplified it. To make matters worse, I misplaced my original Bose seals, so I had to spend another $20.
I'm still on the hunt for the perfect ear seal. I need something that molds around hats and glasses. The silicone seal that the early Bose came with seem like they would do the trick, but you can't find them for the modern headsets which leads me to believe maybe not.
DEM