Compatible: Compatible with any marine boat cover that has tie down loops. Enhanced security at the hem prevents boat cover blown away by strong winds. Keeping the cover stay in place. Durable: Made of 1680D Polyester Fabric, which can be used for a long time and adapt to the marine environment. Easy Loading: Each sandbag bag has 2 zipper pockets, side pocket design for easy access. Size & Capacity: Unfolded size is 18.8"L x 9.4"W, can hold 10lbs. Kit includes: 4 sandbags and 4 hooks. (sand not included) Larger boat covers may require multiple kits.