This is a Sidi Adjustable Heel Retention System for 2012 and later. Slip or friction on the heel cup of a shoe can be both distracting and painful. Dial in an absolutely perfect heel cup fit on your shoes with the Sidi Adjustable Heel Retention system. Fitting just above the plastic heel cup on any current or past model of Sidi's Dragon, Genius, or Ergo shoes, the Heel Retention System may be adjusted with the simple turn of a screw, ensuring a comfortable, performance-enhancing fit. Also retrofits to any shoe model with the non-adjustable Heel Security System.