IIRC, and I could be wrong in my memory of their construction since I haven't used the narrow "isolation" tips in a long long while, I think it might have something to do with the tips continually narrowing until the end of the tip. It's not like the Sony hybrid where it's narrow to begin with at the base and is just stretchy. I have them in a box in storage so don't have immediate access. Anyone else have them on hand?
4/1/15 at 4:48pm