Profile: Marshall Instruments, Inc. is a manufacturer of bimetal thermometers. Our product line includes air & fuel ratio, boost pressure, fuel level, fuel pressure, tachometers, vacuum, voltmeters, and water temperature gauges. We offer bimetal thermometers for industrial and laboratory use. Our thermometers are available in 1", 1½", 2¼", 3" and 5" diameter dial sizes, with a large selection of Fahrenheit, Centigrade, and dual ranges. All our thermometers are available with custom stem lengths from 2½" to 84". Our air/fuel gauges monitor the air/fuel ratio of gasoline engines when wired to an O2 sensor. The AFR gauge can indicate if fuel demand is higher than the fuel system capability, whether additional tuning is required, if there is an intake vacuum leak, or if the O2 as well as other sensors fail. Our general service steel case gauges are economical, general purpose gauges for pressure measurement from vacuum/compound through 5000 psi. These are suited for use with water, oil, air, gas, or other non-corrosive media. Their applications include FRLs, compressors, pumps, boilers, regulators, dryers, as well as commercial and industrial equipment.