Developed in response to requests from the Collins Collectors Association"this is a matching audio transformer for older equipment with 600 ohm audio outputdriving modern speakers. Or for "classic" high impedance speakers used with newer equipmentsimply swap primary for secondary (ie...4 or 8 ohm input and 600 ohms out). Key Features Isolation unit: (i.e. seperate primary and secondary) Primary: 600 Ohm (with 6" wire leads) Secondary: 8 Ohm with 4 Ohm center tap (with solder lugs) Power: Rated at 12 watts Frequency Response: 30 Hz - 20 kHz Weight: 1.3 lbs. Mounting: 2 hole u-bracket mount - on 2-~\frac{3}{16}~" mounting centers.