Check valve housing is made from lightweight alum. and anodized to help prevent corrosion. Housing ends are machined 37 degree flare so they can be installed inline or straight into the barrel valve with the O-ring that is provided with the check valve.
Check valve is typically set at 20 to 200 pounds. Wrench hex is 13/16" on each end. Please specify spring pressure when ordering and if you are not sure let RBS help you.