3 Pack, Brass, Nozzle Plug, Use In Place Of A Mist Nozzle On All Outdoor Mist Cooling System & To Replace Nozzles In The Off Season When The Mist System Is Not Used & The Mist Nozzles Are Being Stored, Prevent Debris & Insects From Entering The Mist Line & Clogging The System, Useful To Plug Off Openings When Less Mist Is Desired.