This new design incorporates a microprocessor. A crystal-controlled 30 Hz. sine wave (not a square wave) is supplied to the electrode pair under test. Leads connect to the electrodes using the industry standard .060' safety jacks. The 1089e supplies simple 'pass-fail' LED indication for the contact impedance ranges of <5KOhm, <10 KOhm, <20 KOhm, <50 KOhm, and >50 KOhm. Simple, single switch operation, with automatic power down, further simplifies the use of this essential, 9V battery powered instrument. 1 year warranty.