BOX USA BEPM15204 Expansion Poly Mailers, 15" x 20" x 4", White (Pack of 100) Strong polyethylene mailers protect products from moisture during shipping Features a gusseted bottom to allow for thicker items such as binders, books and catalogs Puncture, moisture, tamper and tear resistant High strength seams will keep contents intact even if over Packed The outer surface of the mailer is white and the inner lining is Silver