Profile: National Instrument Supply Co. specializes in scientific and laboratory equipments. Our product line includes pressure gauges, transmitters, diaphragm steels, mechanical temperature equipments and steam specialties. Our welded system threaded process connection type M93X.D1 is featured with dual; containment, tamper proof, drop in gauge displacement and with welded design. Our bourdon tube pressure gauge type 111.11RF refrigeration gauge standard series are featured with durable red or blue ABS case, zero-adjustment screw on dial and silicone dampened movement.