We found a few homes in Ohio that needed this fitting, it is rare and you need to messure the one you have to be sure.
Metal Flared Tube Fittings; Type: Flare Cap; Flared Degrees: 45.000; End Connections: Flare; Tube Outside Diameter: 1/4; Material: Lead Free Brass; Max Working Pressure Dynamic: 1,400
Tube Outside Diameter
Max Working Pressure Dynamic
Max Working Pressure Static