The NFP Jazzplate is just an easy way for Jazz bass players to have the NFP filter sound on their instruments. It is solderless and it should fit on most Jazz basses on the market without any adjustments to the control cavity.
The control plate keeps its traditional configuration of Neck Vol and Bridge Vol that is always in-circuit. It has a Passive/Active switch and an NFP Filter potentiometer which acts as the only EQ control.
The NFP is a second-order Lowpass filter with a resonant peak on its cutoff point (4khz) and the potentiometer allows you to sweep from anywhere between 150hz and its cutoff point of 4khz.