Dimensions: 6.5” x 4.5″Thickness: 250 GSMEcoSwift Self-Sealing, Peel and Stick AdhesiveQuantity: 20 EcoSwift Brand Flat Cardboard Mailers with self-sealing, peel and stick adhesive, keep contents secure. EcoSwift Cardboard Mailers are extremely durable and lightweight to help save money on postage and are constructed with strong seams. Surface easily accepts ink, stamps, and labels. Approved by shipping carriers.