Our 36" x 36" x 18" 200#/ECT-32 Standard-size corrugated boxes are designed to cater to all of your shipping and storage needs. The rigid cardboard construction protects contents and stacks securely. These 36 x 36 x 18 shipping boxes are made from 200 Pound test, kraft C-flute single wall corrugated carton. These over-sized standard boxes are designed for shipping or storing those larger and wider specialty items.