Cheshire Mailers envelope stiffeners are quick, convenient, inexpensive, lightweight and reusable. Envelope stiffeners are placed inside a paper envelope for mailing to provide extra rigidity and help prevent bending and folding of the envelope contents. They offer the most versatile, inexpensive and complete mailing protection for currency, stamps, postcards and other similar paper collectibles. These envelope stiffeners are made out of recycled materials and can be reused many times. Single sheet style envelope stiffeners provide one layer of protection (they do not fold in half like the folding style stiffeners). They are white on one side and brown on the other. They are completely blank on both sides so that shippers can add their own branding, advertising or messaging if desired.