Seymour Duncan STC-2P preamp. This preamp works with passive pickups. It has a master volume, blend control and a stacked bass/treble control.
This is brand new (still in the box). I had gotten it for a bass that I didn't end up getting. It's made for a two pickup setup.
Here's a link for SD's main page for this preamp: http://www.seymourduncan.com/product...c2_stc32_3ban/
Asking $90 shipped CONUS.