Unusual extreme sport is wingsuit flying (also known as wingsuiting), which involves flying people with the use of a specially designed jumpsuit known as a wingsuit. The suit enlarges the person’s surface area and increases their chance for lift. Participants are set into freefall with the wingsuit and parachute. Special skills and techniques are required when attempting to exit while wearing the suit. The location of the jump and the size of the door through which the jumper will exit the plane determine which techniques are needed. The techniques involved relate to the flow of air and the type of plane as this influences the jumper’s body position and stance to avoid hitting the plane or being unstable in the wind. The suit significantly complicates what is otherwise just skydiving. As a result, the Skydivers Information Manual, governed by the US Parachute Association (USPA), stipulates that a jumper must have made a minimum of 200 freefall skydives within an 18 month period before being allowed to wear a wingsuit for the first time. Moreover, the jumper must also receive individual instruction from another jumper who is experienced at wearing a wingsuit while jumping. A jumper who has done 500 wingsuit jumps is considered to be an experienced wingsuit jumper. As a result, the manufacturers of wingsuits offer appropriate training courses and certification for instructions. Wingsuits can only be bought if the buyer has made a minimum number of jumps.