Timewave DSP-59+ Ham Radio Audio Noise DSP Filter - Untested - Parts Only

Vintage MFJ-721 Super Selector CW / SSB Amateur Radio Audio Filter - AS-IS

MFJ Enterprises MFJ-751 Tunable SSB / CW Audio Filter - NO Power Supply - CLEAN!

Audio DSP Noise Reducer DNR Digital Filter SSB Ham Radio For YAESU ICOM+Speaker

Audio DSP Noise Reducer DNR Digital Filter for SSB Ham Radio YAESU ICOM+Speaker

Autek Research QF1 Vintage HAM IC Active Audio Filter - Untested - RARE!!

Ham Radio Audio Filter 300Hz-2700Hz Amateur Untested

DAIWA AF-606 All Mode Active Filter with Speaker built in