Various materials are involved in the creation of the perfect crate for an artwork. Polyethylene foaming is used with different density and thickness according to the medium of artwork to pack ; it is usually glued to the wooden part of the crate to create a sort of art cushion or soft bad for the work as we prefer to call it. Aluminium is often used for the isothermal crates and to create the moisture barrier inside. It is glued as well inside the crate. The artwork is never directly placed towards crates elements; tissue paper, plastic bubbles or Tyvek usually wrap the artwork in order to have it protected from direct contact with foaming and another compounds which may be used inside the crate.