Cool Tire Valves

tire valves
A valve stem is a self-contained valve which opens to admit gas to a chamber (such as air to inflate a tire), and is then automatically closed and kept sealed by the pressure in the chamber, or a spring, or both, to prevent the gas from escaping.
(Tire valve) The fitting in the valve stem of the wheel that allows you to inflate or deflate the tire.

cool
Behave in a less excitable manner
the quality of being at a refreshingly low temperature; "the cool of early morning"
neither warm nor very cold; giving relief from heat; "a cool autumn day"; "a cool room"; "cool summer dresses"; "cool drinks"; "a cool breeze"
Become or cause to become less hot
Become or cause to become calm or less excited
make cool or cooler; "Chill the food"