Compatible: Compatible with any marine boat cover that has tie down loops. Durable: Made of thickened PVC Fabric, waterproof and sturdy, which can be used for a long time and adapt to the marine environment. Easy Loading: Each water bag has a water hole, and the cap has a leak-proof silicone ring, no need to worry about leakage. Size & Capacity: Unfolded size is 22"L x 10"W, can hold 17lbs. Kit includes: 4 waterbags and 8 hooks. Larger boat covers may require multiple kits.