I am currently searching for a stryo foam box that will fit inside the USPS express shipping box however this is like a needle in a hay stack. Since I am not able to find this, I was going to use packing peanuts. I have a large trash bag full of these that I keep for shipping things out. I planned on placing coral in bag which will be triple bagged, which in turn will be placed in express box and then I would place packing peanuts completly around entire bag. I would then place an 18 hour heating pack (unless I find a long hr one) into the packing peanuts. For the ones who have shipped corals before, would this work, or could you give me better ideas.