The 240 Kelvin Ratio Bridge is used to compare resistors to a parts per million by either the interchange or substitution method or can read directly by using a decade resistance standard Deviation ranges of ?60 ppm at 1 ppm/div; ?0.06% at 0.001%/div; ?0.6% at 0.01%/div Accuracies to 0.005% can be obtained Multiplier ratios of 0.01, 0.1, 1, 10, 100