ESI-870 Resistance/Resistivity Indicator by element9284 | Feb 27, 2021 Learn More ESI-870 Resistance/Resistivity Indicator LED measurement indictaor. Resolution of one (1) order of magnitude. Includes two (2) each machined brass, one (1) square resistivity configuration. One (1) PUSH to TEST button. Battery operated (1 x 9 Volts) Indicated in Ohms & Ohms/Square.