100 9" x 12" Self-Seal Poly Mailer Bags Durability, Multi-layer, co-extruded film provides optimum moisture, puncture and tear resistance. The Black inner layer provides confidentiality. Water resistant and tamper evident Security high-strength, hot-melted adhesive closure provides additional tamper resistance. Easy opening, reduces labor costs and increases productivity. Self stick labels and labels adhere easily. Outstanding tear strength, no unwanted tears along the seam resulting in perfect delivery every time.