BJFe Sea Blue EQ 5K

Sea Blue EQ (SBEQ5) - Booster pedal with active EQ. This is not a transparent booster. Much more than just an EQ. Warms, fattens and sweetens up your tone.

There’s +-15dB boost/cut 
Treble @7KHz 
Bass@100Hz 
+-12dB boost/cut 
High mid 800Hz 
Low mid 350Hz

It means you can boost or cut bass and treble, as well as low and high mids. If you leave the mids at noon, you can cut mids at 750Hz by boosting bass and treble, and vice versa boost midrange at 750Hz by cutting treble and bass. This is because 750Hz is center frequency from where the axis of treble and bass bend up and down.

Typically on EQ’s the center frequency is 1KHz, but the SBEQ is tuned for guitar, hence the lower center and boost and cut frequencies.