Xtenex Laces are popular with professional athletes; from golfers to distance runners to triathletes. They are also are perfect for anyone who wears casual shoes, senior shoes, orthopedic shoes, medical shoes, diabetic shoes, children’s shoes and everyone else in between. The Xtenex X300 Series elastic laces fit ANY shoe that has an eyelet size of approximately 3 to 4 mm. They are a perfect choice for most activities involving normal foot movement; from everyday wear to running. These were the laces worn by Jan Frodeno (Gold Medalist) and Simon Whitfield (Silver Medalist) during the 2008 Olympic Triathlon in Beijing, China.