Earl's is pleased to release a new one-way check valve that is ideal for use on fuel and oil systems. Now offered with internal stainless steel hinge and GF-600S Viton seal. The GF-600S Viton is the highest quality seal material for all types of fuels including diesel & alcohol. The Internal spring releases to full flow at 1 psi (Note: blowing through it will only partially release the hinge). High PSI Rating is 1250 PSI. This product uses a proven military design & provides for a more compact unit over conventional flapper check valves.