IMMEDIATE SAME DAY SHIPPING Double NFP Preamp The NFP is a filter preamp alike the ones seen on basses like the Alembic or Wal. Being a low pass filter, it lets all bass frequencies pass through up to 4Khz where it starts cutting. The cutoff point has a resonant peak that can be boosted by pulling-up on the potentiometer. The potentiometer also allows you to sweep the cutoff point(resonant peak) within a range of 100Hz to 4khz on the Neck and 220Hz to 4Khz on the Bridge. The Double NFP has one filter per pickup ,offering more tone shaping options, that are actively mixed through the pan/blend potentiometer and into a Master volume potentiometer. WORKS WITH PASSIVE & ACTIVE PICKUPS.Operation: 9 to 27volts Current Draw: +- 4.5 mAh Dimensions: Filter boards x2: W: 3.3cm; H: 2.3cm; D: 1.7cm Potentiometers:: Hole size is 6.5mm, and bush height is 10m, (use with 6.4mm knobs) Blend board x1: W: 3.9cm; H: 2.5cm; D: 1.3cm MSRP : $309.00 Lusithand PREMIUM CUSTOM KNOBS now available, check out my other listings.For lots of great videos of LUSITHAND high end products, go to YouTube.