4 Freed Line Input Mic Phono Step Up military Transformer Matching Pair. Dc resistance pin 1 and 2 is 4ohm on all. Pins 3 and 4 read 342ohms 345ohms 356ohms 370ohms . Very tight dcr matching pair. Perfect for a variety of very useful hifi applications. Leads exit through glass seals. Killer military bulletproof transformers! There are 4 total. One is a slightly different case style but same part number. See pictures.