The 998 Series One Way Check Valves are made with a heavy-duty corrosion-resistant iron housing. The 998 is perfect for extremely high air flows with its 1" NPT porting. Each have a soft "O" ring style leak proof sealing and an in-line cartridge. The cartridge design allows for in-line servicing resulting in a significant reduction in costly out of service time during maintenance. The check valve cartridge is designed with a spring for positive action and stainless steel shuttle that seals on an "O" ring to eliminate compressed air leakage. Several configurations with orifices are available and marked for quick reference. In addition, the GW 5998-050 Series Orifice Adapter can be used with the 998 Series Check Valve to control flow and eliminate the need for a second in-line check valve.