The preamp delivers limitless EQ and tone shaping control at your fingertips and empowers you to tailor your sound to perfection, with a wide range of wiring and application options. It can be configured to operate at either 9V or 18V, and has extraordinarily long battery life as a result of its remarkably low power consumption. The MB INSTRUMENT PRE P version also includes the same pre-wired controls and accessories featured on Markbass instruments - including six potentiometers, a polyester capacitor, a 9V battery connector and an output jack - simplifying the electronic customisation of your bass.