The Thrush Co. Inc. Aar-O-Vent is the ultimate solution for air elimination and dirt separation. If you have experienced failures due to contamination or air entrapment, consider installing an Aar-O-Vent in your closed loop piping system. Standard sizes are in stock and ready for immediate shipment. Here are some other reasons you should consider an Aar-O-Vent for your application: Unparalleled performance Removes nearly 100% of dissolved oxygen content in closed piping systems Patent pending design Improves efficiency and longevity of closed piping systems