Used Broughton Low + High Pass Filter Bass Effect Pedal | Musician's Friend
NPD - Broughton Low + High Pass Filter. Does a great job of cleaning up muddy low end and hissy high end frequencies I don't want. Just the creamy middle! : r/BassGuitar
SMALL FI BASS CUT LO FIDELITY EFFECT PEDAL PASSIVE EQ HIGH PASS FILTER LOW | eBay