jj You are right, but...
since I had the original 1988 Mac 26D outside cushion which did not appear to be closed foam and was not mildewed, I chose to go with the $29 foam.At my age, and given the age of the original cushion, I calculated I'd be "food for the fishies" long before mildew overtook my handiwork. Let the new owners deal with it. They likely won't be living on social security, as am I. ;^)I even salvaged the original zipper which appears like new after a couple of hours soaking in Oxi-Clean.I'm not advocating anyone do as I did... only explaining how I was able to get new cushions at a price I could afford.