I have a pair of E500 headphones. They were immediately the best headphones I've ever heard - yet, I never really got a "good seal" with any of the standard sleeves (yellow foam, clear, black, et al).
These are, by a long shot, the best sleeves you can get for your Shure headphones.
They expand to form a perfect seal, that is leaps and bounds more comfortable than any other choice. Having a tight seal was difficult for me with the default sleeves because there is a very slight variation in the size of my ear canals. These sleeves perfectly address that issue and form the tightest sound isolation possible with an extremely comfortable fit.
If I could give them 10 stars, I would!
If you've bought Shure headphones, then you are concerned with quality of sound. You will enjoy your headphones even more with these sleeves.