SP stands for Siège en Plastique, and the chair is an updated version of Jean Prouvé's classic Standard chair. Without compromising on form, the Standard SP is made from sturdy plastic, and the seat and back rest come in a variety of colors. Jean Prouvé realized that the greatest strain is on the two rear legs of a chair, and subsequently designed the Standard chair but with significantly stronger rear legs. The two front legs are thus thinner and carry the least load.