This Omer Wishbone Kit features two nylon spheres with a Dyneema eyelet that have to be inserted in the rubber bands and tight by a constrictor knot. The extra piece has to be linked to the eyelets to complete the wishbone. You can very quickly and easily replace wishbone while at the beach or on the boat. Wishbones are one of those essential spares you need in your save-a-dive-kit. So don't let a broken band ruin your day of hunting for that trophy fish by having spare spear gun bands in your kit.