150 Medium courier bags metallic blue tough and strong, Suitable for items of clothing and books or similar sized items. All of our Plastic postage bags are made from Strong Polythene LDPE and are 55 Micron thickness, 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 , The sizes quoted don’t include the flap.