Heavy-duty triple wall cardboard corrugated boxes 30″ x 30″ x 30″ 1100#/ect-90 – 5 pack these containers are as strong as a plywood crate, but at the cost of corrugated. perfect for shipping heavy items such as small motors, compressors or valves constructed from 1100# tw/ect-90 kraft corrugated additional thickness provides extra protection, security and stability during shipment rsc = regular slotted container sold in bundle quantities of 5 for help selecting the right box, click the brochure tab below.