Our 15x20'' Expandable Poly Mailers 300/case is made from a co-extruded blend of Low and Linear-Low Density Polyethylene, our Poly mailers are white on the outside and silver on the inside. The envelope makes shipping clothes, t-shirts, fabrics, scarves, etc very easy.Type=Co-ex PEStyle=SideweldThickness=2.5 milWidth=15 in.Length=20 in.Color=WhiteQty/Case=300Feature=Bottom Gusset 4.00 , Lip Size 2.00