There are several foam tips to choose from.
There are 3 official tips from Ety. http://www.etymotic.com/ephp/er4-acc.html
The small beige, the medium black and the large yellow
2 from Shure (the ones for the E3c will fit) http://www.shure.com/americas/products/accessories/earphones-headphones/sleeves/index.htm
The very popular black "olives" (small, medium and large) and yellow (one size fits all)
2 from Futuresonics
Black (small and...