Hex Head Cap, 3/8 in Nominal Pipe Size, Brass, Female NPT, -65 Degrees to 250 Degrees F, Includes Pre-Applied Thread Sealant No, Includes Seal No, 3/8-18 This GRAINGER APPROVED cap is suitable for use in water, oil, natural gas, and steam applications.⢠NPT connections⢠Temp. range allows use in extreme conditions.