Where can we buy eartips for the IER-Z1R in the United States? I have two concerns 1) ear wax may enter the enclosure - it doesn't look like IER-Z1R has filters like the Etymotic ER4XRs 2) I swap eartips out often to keep them fresh and get good seals, but I can't find any waxguard type eartips...

Hi, I am thinking of picking up the IER-Z1R, but I can't seem to find where to get more tips. What is the lifetime of the foam-type tips?