EUW-28 Resistance Substitution Box The Heathkit model EUW-28 Resistance Substitution Box is a handy laboratory aid that makes a wide range of resistors (36 different values) readily available. This makes it possible to experimentally determine the value of most any resistance that is required in a circuit. SPECIFICATIONS -------------- Range . . . . . . . . . . . . . . . . . . 15 ohms to 10 Mohms Accuracy . . . . . . . . . . . . . . . . +/- 10% EIA values Power Rating . . . . . . . . . . . . . . 1 watt, all values Voltage Rating . . . . . . . . . . . . . 500 volts maximum Dimensions. . . . . . . . . . . . . . . . 4-3/4” wide, 4-1/4” deep, 5” high Net Weight. . . . . . . . . . . . . . . . 1-1/2 lbs.