This is a HUMPBACK ENGINEERING 1x2. It's an onboard preamp. It has a 2-band EQ for bass and treble. I had it installed in a Fender Jazz Bass, and it's the "original sound-focused" type that's popular these days, boosting and cutting the original sound. If you're looking for a big change, something like a Bartolini would be better. Please see the images for the adjustable frequency bands. The wiring to the pots is as it was when I was using it, with the order being volume, balancer, treble, and bass. I used it without an on/off switch. I don't have any wiring knowledge, but I think someone who knows about wiring could use it right away with a little work. *See wiring diagram* I had the installation and removal done at a musical instrument store in Tokyo. It was in use until recently, so it works fine. Price reduced from 17,000 to 16,500. I will not be lowering the price further. Also, the price is set considering the pots are already wired. Thank you for your understanding. #bass #preamp #humpback #HUMPBACK ENGINEERING