Strong sticky gel base is added to the suction cup to provide a stronger hold. The suction cup will work in cold or hot environment. These stick and hold wonderfully on a smooth surface (like a car or glass), however, no plastic surface suction cups will stick if there is any texture on the surface. Each anchor can hold up to about 20lbs, long lasting hold and it won't come loose until you take it out.Provide very strong handles on smooth surface. Includes versatile wide door spring hooks and attaches via heavy-duty webbing. These suction cups stick to smooth fiberglass surfaces like glass, boats, cars, and RVs. Perfect for when you travel, you can connect two cars to hang your clothes, tent, awning, and you can hang everything, which is convenient to use and carry. It works on most smooth surfacesnon-porous. cup hooks will hold its place as long as needed.