Aguilar OBP2SKSET 2-Band Boost/Cut On Board Bass PreampActive electronics and preamps give you bands of EQ to shape your bass's tone. Using these active EQs lets you find your signature sound directly from your bass. Aguilar sets the standard for aftermarket onboard preamps. The Aguilar OBP 2 runs at 9V or 18V and gives you the benefits of active electronics while being compact enough to fit into just about any instrument. You get two bands with 18dB boost cut at 40Hz and 16dB of boost cut at 6. 5kHz,