Beautiful heavy solid brass tap marked CALCO USA (probably just before WWII, late 30s, early 40s?). This has an amazing patina, a deep tarnished bronze color.
There's a little chipping and wear on the threads, but it looks to us very useable yet. The fitting is sized for 1/2" iron pipe, and it takes a standard garden hose fitting at the outlet. Measures 4" long overall, 4" high.