Our 18 x 8 x 4200#/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 18 x 8 x 4 shipping boxes are made from 200 Pound test, kraft C-flute single wall corrugated carton. Our standard corrugated boxes are great for shipping or storing round, narrow and large-size items.