Dwyer Instruments”BTG bulk tanker gauges feature PSI scales with 1 percent full-scaleANSI B40.1 Grade 1A accuracy. The 4.5″ BTG gauges are designed with anepoxy-coated black steel housing that is rust and corrosion resistant.The BTG gauges are designed with a silicone dampened counter weightattached to the movement, which allows the units to withstandvibration. Wetted parts include a brass socket and phosphor bronzebourdon tube. Units can withstand temperatures of -40 F to 160 F (-40 Cto 71 C). Units come with a _” male NPT bottom connection. The gauge isdesigned for use on tanker trucks for monitoring discharge pressureswhile the tank is being unloaded.