The highest-quality socket-connect fittings available, these meet ANSI/MSS SP-114 standards for heat treating, material thickness, and marking. Also known as Pressure Class 150 fittings, they are designed for low-pressure applications. Socket-connect fittings are easier to weld than butt-weld fittings because the fitting doesn’t need to align perfectly to the pipe. Slide pipe into the socket and weld for a strong, permanent connection. 304 stainless steel fittings have very good corrosion resistance.