These envelopes are cost effective for sending newsletters and cards that are 8.5"x11" letter size folder in half. It is a more effective format than a trifold. And there was no difference in postage costs.
These envelopes are not of good quality. When using them to send items by mail - they tear apart easily in the USPS machines. I have to use packing tape to seal the envelopes on the top and the bottom to make sure they do not get ripped open.
We use these envelope as communication envelopes for our teachers and parents. It is a great size for documents that need to be retained but not take up a great deal of space