A set of four plates, approximate 4-inch square by 1/4-inch thick UV treated polyethylene plastic. Each has 2-foot of quarter inch thick bungee cord and s-hook attached. Bury plates down into the sand about a foot. The weight of the sand is what holds them in place. Bungee cord attaches to corner loop of your boundary with s-hook. One year limited warranty against manufacture and material defects.