The 699 Series One Way Check Valves are made with corrosion-resistant cast aluminum. The 699 has a custom flange face to adapt to specific air brake manifolds. 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.