This is the XS Scuba Highland Technical Straps Spring Strap Attaches to most brands of scuba fins Features: One kit attaches to most brands of scuba fins High quality stainless spring & buckles will not rust Streamlined thumb pull will not snag Internal cave line to prevent over stretching of springs Includes old school buckles for rubber fins & large post buckles for most modern fins Available in three sizes p/n HL708 Spring Length 8 / 203mm Overall Length 10.5 / 267mm p/n HL710 Spring Length 10 / 254mm Overall Length 12.5 / 318mm p/n HL712 Spring Length 12 / 305mm Overall Length 14.5 / 368mm How to select the proper size Highland Technical Spring Straps? Insert your foot into the fin pocket while wearing a boot Measure from the attachment point on one side of the fin, around your heel, to the other side Choose the spring straps with an overall length that is approximately 1 inch shorter than this measured distance Spring heel fin straps are popular because they are comfortable, easy to use and practically indestructible. Highland premium spring fin straps are made from stainless steel springs and covered with nylon tube webbing to protect the spring and keep out grass and other plant matter. The thumb puller is streamlined and designed not to snag on objects like traditional finger loop designs can do. The springs have machined Delrin ends that attach to one of two types of stainless steel adapter fittings with a stainless screw and nylon lock nut. Nylon line on the inside of the spring prevents over-extension of the strap.