The 599 Series One Way Check Valves are made with a heavy-duty corrosion-resistant iron housing. The 599 is available with 3/8" NPT porting and can be mounted inline. Each have a soft "O" ring style leak proof sealing and an in-line cartridge. The cartridge design allows for inline 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 a 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.