LDPE film is heat sealable, chemically inert, odour free and shrinks when heated. It is a good moisture barrier . Low-slip properties can be introduced for safe stacking, or conversely high-slip properties permit easy filling of packs into an outer container. It is less expensive than most films and is therefore widely used for pouches, bags, coating papers or boards and as a component in laminates. low-density polyethylene (LLDPE) is used at thicknesses of 17–24 μm. This material has a highly linear arrangement of molecules and the distribution of molecular weights is smaller than for LDPE. It therefore has greater strength and a higher restraining force. The cling properties of both films are biased on one side, to maximise adhesion between layers of the film but to minimise adhesion to adjacent packages.