This output transformer was removed from a working Hammond L100 organ. It powered 2 EL84's in push pull. The transformer has an voltage ratio of 30/1 so the impedance is 7200 with a 8 ohm load. The resistance of both the primary and secondary has been tested as well. The mounting holes are 3 1/4". The transformer measures 2 1/8 tall by 2 3/4 wide. The transformer weighs 1.9 pounds. Please feel free to ask any questions prior to purchasing and we will be glad to help you.