Grey Mailing Bags Size 250mm x 350mm or 10" x 14" + Lip, Qty 500 100% Opaque-100% Recyclable and degradable. 250mm opening x 350mm depth + Lip ( 10 x 14 " ) The sizes quoted don’t include the flap. Our mailing bags are made in a 3 layer extruded film. This film gives the bags strength and most importantly, makes the bag very opaque. We also get them made thicker than our competitors, The thickness of the film is 50mu or 200gauge. All of our Plastic postage bags are made from Strong Polythene LDPE, made from opaque Plastic in various colours. They have a permanent Peel and seal closure with high tear resistance. How to find the correct bag for the items you are despatching, firstly lay out your item and measure the long and short dimensions of it, and then check the sizes quoted in the Heading above are close to the size you need ,