I have used these extensively on my GT40, Cobra, several street rods and my daily drivers. I have never had one single problem with them leaking or coming off. In fact, on one project that was double clamped with standard hose clamps the only way I could keep the hose on the water pump was using these shrink tube clamps. They are easy to use and look very sanitary. If you are worried that they will blow off down the road, carry a spare clamp. As stated above however, I've never had one fail with tens of thousands of collective miles on 8 cars. These are used on many OEM applications also.