The bulbous Up5 Chair by Italian designer Gaetano Pesce follows on from the 20 iconic seat designs we've already featured for our A-Zdvent calendar.

First designed in 1969, Gaetano Pesce's Up furniture series is made from expanded polyurethane foam and upholstered in elastic synthetic jersey.

The most recognisable forms in the set of seven pieces are the Up5 Chair and accompanying Up6 Ottoman, which together have become icons of Italian design.

As the products are mostly air, they can be transported vacuum-packed flat at 10 per cent of their final size. Once removed from the packaging, the spongy material fills with air and inflates without the need for a mechanical device.

The chair was delivered using this method during its first production period – from 1970 until 1973 – by furniture brand C&B Italia. The brand has since changed its name to B&B Italia and re-released the design in 2000.

Up5's anthropomorphic shape and the string that connects the spherical ottoman to the base are both references to his "notion of women", according to the designer.

"I was telling a personal story about my notion of women: despite themselves, women have always been prisoners of their own making," said Pesce.

"Along these lines, I liked the idea of giving this armchair a feminine shape with a ball and chain, the traditional image of the prisoner."

The elasticated fabric cover for the chair is available in a range of colours, as well as a version with beige and orange stripes influenced by the original 1969 model.

B&B Italia also produces the designs in smaller UpJ versions for children.