You can really get a lot in these and quilts fold a lot easier to go in also. I have put a large quilt in one and 15 yds of canvas. Haven't tried fabric yet as no sales. LOL. Thought you might like to see you can order these at USPS.com and the new bubble small priority. I order them all the time. Love them.
USPS.com ahs lots of free boxes that you cannot get at the local USPS.