Hi!
The specific brand foam sleeves used by Future Sonics for the M5/M8 are the same than the one used with their former model, the EM3.
I have found the following quote and, very similarly, I share the same experience:
"Only one small issue or complaint I have with the EM3’s, and that is the use of foam sleeves. If you don’t keep your ears scrupulously clean, then after a few wash and dries of the sleeves, you’ll need to get replacements, as the originals won’t come back to their initial fullness and shape – the front is likely to be angled instead of perpendicular. So, when you buy the EM3’s, be sure to add on a few (10/pk) replacement sleeves at the same time.
http://www.lordpercy.com/future_sonics_em3.htm
I personally do not wash the pair of sleeves I used but after 2 to 3 days of usage they shrink! And consequently seal less well! Today I compared the other pair I had not used yet and their is a difference in size.
I ordered a replacement (10) set of foam sleeves from Future Sonics today.
Up to now it is with those foam that I got the better sound out of the M8.
I wonder if the following, found at ebay, at the seller Idealsound will be a correct replacement for the foam sleeves?
These are the yellow ones.
Universal Fit Foam Sleeves
For E3c, E4c, E5c, E500, i3c, and i4c versions. These reusable, disposable foam sleeves compress to fit gently into the ear. Once in the ear, the foam expands to form a tight yet comfortable seal that holds the earphones firmly in place. The E3c, E4c, and E5c come with one pair of universal fitting yellow foam sleeves.
EA120 - 10 pair (replaces PA750)
LIST PRICE $25
OUR PRICE $23
http://cgi.ebay.ca/ws/eBayISAPI.dll?...MEWA:IT&ih=013