{Sheet blow-moulding, i.e. using at least two parallel sheets or a folded sheet as a preform whereby the folded sheets or the two parallel sheets are separated from each other at least at one place, e.g. to allow inserting of a blowing means}
{Sheet blow-moulding, i.e. using at least two parallel sheets or a folded sheet as a preform whereby the folded sheets or the two parallel sheets are separated from each other at least at one place, e.g. to allow inserting of a blowing means}