*PLUMBERSSTOCK EXPERT* responded:
Hi! Can you tell us more of what you want to know? In copper pipes, the outside diameter is the controlling dimension. Based on this catalog, this Arrowhead 254CC hose bibb features a 1/2" Copper compression connection by a 3/4" Hose Thread connection. Meaning, one end goes on to a 1/2" copper pipe while the other end can connect to a 3/4" hose. Hope this helps! If you have further questions, feel free to post them here. Thanks for visiting PlumbersStock.com!