The Apeks Spring Straps with Heel Pad are designed to be used with Apeks RK3 Fins (see SKU's: APXFRK3 & APXFRK3HD). Easy to use springs automatically compensates for different size feet and boots. Spring fin straps are depth compensating because they will compress to changes in the thickness of your boots. No need to adjust straps once you have descended to depth or once you ascend to the surface at the end of the dive. These corrosion resistant fin straps come in multiple sizes.The Apeks Spring Straps with Heel Pad have custom designed buckles that hold the straps in the optimum position for donning, doffing and when finning. Straps are equipped with a rubber heel extrusion that provide comfort while finning and the large heel grip tab makes for easy donning and doffing even when wearing thick gloves. Simple push pin design allows simple replacement of springs if necessary, making them a great save-a-dive-kit item. Remember the dive you save may be your own! Spring straps are available in multiple sizes.