Locknut, 3/8 in Nominal Pipe Size, Class Class 125, Red Brass, Female NPT, 125 psi Maximum Operating Pressure, -20 Degrees to 400 Degrees F This GRAINGER APPROVED locknut resists corrosion from water, heat, saltwater, acids, minerals, and soils.⢠Temp. range allows use in extreme conditions⢠For use with air, water, natural gas, and steam.