The preform heated at about 110°C is then inserted in a hollow mould whose shape corresponds to the shape of the finished bottle. The shaping of the bottle happens through a double simultaneous action: the stretching of the material using a blowpipe introduced in the neck of the preform and a transversal forming of the bottle by blowing compressed air in the preform, hence the name ‘stretch blow moulding’. Once cooled off the bottle is ejected from the mould and has – because of the stretch blow process in the thermoelastic phase of the material – higher mechanical properties than the same bottle produced by extrusion blow moulding. The latter technique is therefore used for the production of sparkling beverage bottles and transparent detergent bottles. When reheated the bottle will go back to the size of the preform.