A hula hoop is a toy hoop that is twirled around the waist, limbs or neck. They have been used by children and adults since at least 500 BC. The modern hula hoop was inspired by Australian bamboo hoops. The new plastic version was popularized in 1958 by the Wham-O toy company and became a fad. Hula hoops for children generally measure approximately 28 inches (71 cm) in diameter, while those for adults measure around 40 inches (1.0 m). Traditional materials for hoops include willow, rattan, grapevines and stiff grasses. Today, they are usually made of plastic tubing.