J Heel. The ORIGINAL PATENTED, made in te USA J Heel. Not the knockoff you may find on other sites. Converts a regular track shoe into a multi-purpose track shoe for jumpers and throwers. Use on plant heel for javelin or plant heel on "J" approach to high jump. This versatile heel can be used by a number of athletes for different events or by one athlete for multi-events. One size fits all - adjustable, can be used on right or left heel, will not roll or slip, made with light high-quality material. TJHEEL is legal in all states for competition as per NFSHSA rule 7-2-8.