Model 2793 resistance box is high-accuracy, stable DC variable resistor with 6 dials and is available in two styles: 279301 for medium resistance from 0.1 to 1. 111.210 in 1 m steps (best suited for calibration of resistance thermometers or bridges); 279303 for high resistance from 0 to 111.1110 M in 100 steps (suitable for calibration of insulation resistance testers or bridges).