B&K Mueller manufactures the QuarterMaster series of ubiquitous Anti-Siphon Frost-Free Silcocks. I have also seen people call them Frost-Proof Wall Hydrants, outside water faucets, taps, valves and spigots.

QuarterMaster silcocks come in lengths from 6" to 14" in 2" increments. When I needed to replace one of my old outside faucets, I decided to use the 12" QuarterMaster, which was conveniently available from my local Home Depot.