4" x 18" Kraft Mailing Tubes with Caps. Economical kraft mailing tubes are great for document storage or for mailing. 3-ply spiral wound construction for strength. White end caps (included) snap into place to hold contents secure. Caps will not pop off during shipment. Tubes are reusable and recyclable. Sizes listed are usable space. Actual tube lengths are longer. Additional white end caps available under Part #MTCAP4. Case of 15.SHPP4018K. P4018K. Shoplet select Shoplet select Kraft Mailing Tubes with Caps.