Dail 1.5"-4" Stainless steel case Brass internal Bottom or back connection Good ... and connection. Specifications are as follows:1) Dial size: 1.5", 2", 2.5", 3", 3.5", 4", 6"2) Connection size: 1/8", 1/4", 1/2", 3/8"3) Connection threads: npt ... , bsp (g, pf), bspt (zg, pt)4) Material ...