These are lead free brass nipple sets (2 nipples included) for the WM-PC Series water meter. You will need the original plastic nut that came with the meter. If you need to purchase the plastic set, see Plastic Couplings for WM-PC Meters. This is a great option for when you're installing the plastic meter in a copper or brass pipe system.
Note: Photo represents the brass nipple and the plastic nut (not included) assembled.