Our blue corrugated cardboard mailing boxes are perfect for any subscription business, as literature mailers, presentation box, luxury packaging, sales kit or great for any gift idea. Clear and brilliant blue color paper ensures aesthetics while ensuring superior performance. Our blue flat mailer boxes are made from 100% secondary fibers and are chlorine and acidfree. Sustainably sourced & recyclable. Buy mailer boxes wholesale from Upack. Design online: add your logo and let your brand stand out! Measurements shown are outside dimensions.