Dail 1.5"-4" Stainless steel case Brass internal Bottom or back connection ... 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 ... mmHg)7) Accuracy: 3% - 2% - 3% , ?.5%Inner Packing:Paper box, special printing acceptedOuter Packing:Cartons, packed in PVC/Steel/Wood Pallet 2.5' Glycerin Filled Gauge