Made of heavy 10.5 mil woven polypropylene tarp material. Seams are sewn with mildew-resistant thread. Reflective silver on the outside & UV-resistant black on the inside. Straps & buckles on the bottom to cinch; flaps on bottom fold up to make room for forklift blades. Clear document pocket on outside to ID contents.
These are as tough as they come. With a little common-sense care, they should last for a year or more.