Penny, it doesn't look as if you're going to get a sensible answer unless
you tell people what you want it for!

I use it for for covering books and, no, I haven't found anything suitable
here in Japan. The plastic the Japanese use for covering books is pretty
useless, and the only thing locally available that does the job at all well
for my purposes is a kind of tissue paper.

I order Mylar online from overseas suppliers.

--
John
http://rarebooksinjapan.com