For Sale: 3 microphone transformers, all 8-pin octal base. 1. RCA MI-12399. Primary 250 ohms, Secondary 50,000 ohms. 2. RCA MI-12398. Primary 50 ohms, Secondary 50,000 ohms. 3. Western Electric WSM 161. Primary 50/200 ohms, Secondary 50,000 ohms. All three for $18 shipped CONUS. 73's Pat K9HF