Self-Sealing Cardboard Mailer Brand: FS Thickness: 250 GSM (.010″) Extremely durable and lightweight cardboard material helps provide bend resistance Self-sealing, peel and stick, adhesive keeps contents secure and tamper proof Surface easily accepts ink, stamps, and labels Approved for USPS, FedEx, UPS, and DHL Size / Dimension Available: 4.5″ x 6.5″ 6″ x 6″ 6″ x 8″ 7″ x 9″ 9″ x 11.5″ 9.75″ x 12.25″ 11″ x 13.5″ 12.5″ x 9.5″ 12.75″ x 15″