Bought as a NOS Fidelity Research's first silver coiled moving coil, the FR-1 MK3F !
BOX, MANUAL NO ISSUES
CALL TO RESERVE 780.991.1960
Frequency response 10-50,000 Hz, Output voltage 0.10mV , VTF:1.3 to 1.5grams. Load resistance:over 2.5 Ohms. 7.o grams