Low cut filter switch with status LED helps remove rumble from open mics while the bypass switch with LED indicator is convenient for sound checks. Select between 6 dB or 12 dB cut or boost over frequencies ranging from 20 Hz to 20 kHz. WE APPRECIATE IT!PV® 231EQ Dual 31 Band Rack Mount EqualizerThe PV 231EQ dual 31-band 2/3 octave graphic EQ brings quality features and low pricing together. We will be able to resolve any problems directly and make sure that any issues are resolved.Our near perfect feedback speaks for itself.THANK YOU FOR YOUR BUSINESS. If - for any reason - you have any issue with your purchase, please contact us and we will get right back to you and work with you to resolve any problems.Please do not open any cases or claims without contacting us first.