They use elastic bump technology to hold customized tension throughout all eyelets. Invented in Japan by a marathon runner, Caterpy Laces strives to solve all shoelace issues. These issues range from inconsistency of tension throughout the shoe, lack of adaptivity for different foot shapes and inconvenience of tying laces. Often times, people think foot pains develop from an improper shoe, when it may be from improper laces. Although Caterpy Laces are designed for athletic wear, the product is popular among other markets including kids, elderly, medical and special needs. They're the perfect fit from joes to pros!