The RAYMER MODEL MT-3 microphone matching transformer is designed for use with MICROPHONES . Its universal compatibility allows it to fit a variety of brands, while its 8 pin octal tube socket mount type ensures easy installation. With its NOS manufacturing year, this transformer is a reliable and high-quality component for enhancing your radio communication equipment. Ideal for ham and amateur radio enthusiasts looking to improve their setup, the RAYMER MODEL MT-3 delivers consistent and clear audio performance INPUT IMP. LOW Z 40 OHMS OUTPUT IMP. HIGH Z 4150. OHMS.THIS TRANSFORMER FITS STANDARD 8 PIN OACTAL TUBE SOCKET.. PINS 2-4 INPUT PINS 6-7 OUTPUT.