A replacement SIRE Heritage 3 preamp. This is the preamp used in several SIRE models and it also sounds great when used to upgrade other makes of Jazz bass.
The preamp comes with a battery box and battery snap for 9V operation but you can easily add a second 9V battery for 18V operation giving higher headroom.
Please read and understand the wiring diagram before you attempt installation. I cannot accept returns if you modify the circuit in any way.
You will need a stereo (switched) jack socket in order to turn the preamp on and off when you insert or remove the jack plug.