These are quick connect and disconnect adapters for a variety of pumps used to inflate tires, balls etc. For a high pressure tire such as on a road bike (over 40 psi), you need a head that goes to the tire valve to be able to disconnect quickly so that the air does not leak out while you are unscrewing the usual heads that come with the pumps. This adapter worked fine for my road bikes that need about 80 psi. Once you have them installed on the pump, you can leave them there and use them for everything. They work very well on car tires too.