... internal Bottom or back connection Good quality Liquid Filled Gauge w/Bayonet RingFor anti-shock use, stainless steel ... 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 ... mpa; in Hg, cmHg or mmHg)7) Accuracy: 3% - 2% - 3% , ?.5%Inner Packing:Paper box, special printing acceptedOuter ...