I put these on the firebox cover of my grill/smoker. After I added the sealing tape there are literally no leaks. There are also a few small leaks, but not from the firebox lid. Rubber softens, heats up, but does not melt. If it ever looks like it's going to melt, I just cut them off with a razor. Works fine the way it is now. In the attached picture these are small latches on the chamber on the smoker's right side. The rest are interlock switches.