3" x 18" Green Mailing Tubes with Caps. Mailings are sure to attract attention with these bright colored tubes. Tubes have a glossy finish. Use to identify or categorize different types of documents or mailings. Strong 3-ply spiral wound construction. Tubes seal with white plastic end caps included in case. Sizes listed are inside usable dimensions. Additional white plastic end caps available under Part # MTCAP3. Case of 24.SHPP3018G. P3018G. Shoplet select Shoplet select Green Mailing Tubes with Caps.