A strong adhesive gel base is added to the suction cup to ensure a stronger hold. The suction cup works in a cold or hot environment. These stick and hold beautifully on a smooth surface (e.g. a plastic suction cup, however, will not stick if there is a structure on the surface. Each anchor can hold up to approx. 20 pounds, provides long-lasting hold and will not be damaged. It will not come off until you take it off. Provide extra strong grips on a smooth surface. Includes versatile wide door spring hooks and attaches with a sturdy strap. These suction cups stick to smooth fiberglass surfaces such as glass, boats, cars and RVs. Perfect for travel, you can connect two cars to hang your clothes, tent, awning and hang anything, convenient to use and carry on most smooth, non-porous surfaces. The cup hooks will stay in place as long as needed.