Quantity : Four suction cups per package . Our suction cup is attached with sticky gel base - Much stronger hold strength —— Double suction Includes versatile wide gate spring hooks and attaches via heavy-duty webbing , These suction cups stick to smooth fiberglass surfaces like glass, boats, SUPs, cars and campers Versatile Usage - perfect for tie down applications where there isn't an anchor point, cleat or other device to anchor conventional tie downs. Suitable for smooth surface - These do stick and hold wonderfully on a smooth surface (like a car or glass), however, any plastic surface suction cup will not stick if there is any texture to the surface whatsoever. It's the nature of the beast. If air can get in, the suction will not hold because it relies on creating a vacuum. No Residues - No Glue -Strong Sticky gel base is added to the suction cup to provide stronger hold. The suction cup will perform in cold or hot environment. Long Lasting hold, will not come off until you remove it. Provide very strong grips on smooth surface.