Gravity boots
(重定向自Inversion system)

Gravity boots are ankle supports designed to allow a person to hang upside down. Thanks to exposure in television dramas and movies in the 1980s, gravity boots became a common fitness tool in homes across the United States.
Today, gravity boots are used by the U.S. Army and have experienced a surge in popularity in 2006 with The Da Vinci Code author Dan Brown praising them as well. Several companies manufacture and market gravity boots under various trade names.