They look like a typical hose bib on the side of your house, however these boiler drain style valves are use on irrigation systems to allow hook of of an air line for winterizing of your system in the fall.

Typically these valves are installed where the water supply line leaves the house and before the control valves on the irrigation system.

They can also be used to connect a hose to as long as the system is in use for the summer season.

All Brass construction with a rising stem.