Elenco RS-500 Resistance Substitution Box Use to determine desired resistance values in circuits under design or test Resistance obtainable is from 0 omega to 11,111,110 omega in 1 omega increments All resistors are 1% precision, 1 watt resistors Sturdy construction will keep this handy tool ready for many years of use For 30 years Elenco has been using their strong engineering and design skills to develop reliable, affordable electronic test equipment, tools, and educational kits