Analog Compliance Verification Surface Resistance Checker used for determining if a surface is dissipative, conductive or insulative. Automatic Test Range Voltage Selection Per Compliance Verification ESD TR53 starts tests at 10 volts and automatically switches to 100 volts if the measurement is over < 1 x 10^5 ohms. Portable Operation with 9 Volt Battery no charging or sourcing of special batteries needed. LED Illuminates When Battery Power is Low prevents operator from making bad measurements. NIST Calibrated with Certificate Included calibrated with accepted procedures and standards traceable to the National Institute of Standards Technology. Made in the USA