Mail tray strapping for USPS Bulk Mail Tray strapping requirements is self-locking with notched holes that fit together and lock. Easy to use, no equipment required. Simply cut with scissors to fit the length of bulk mail tray you are using. This strapping is yellow, 5/16" wide and meets the tensile strength the US Postal Service requires for bulk mail tray strapping. Each postal tray requires approximately 5-1/4 ft. This product is NOT RECOMMENDED for any use other than to strap US Postal mail trays for bulk mail.