Replacement EQ unit only for pre-2013 versions of the Oscar Schmidt OS45CE (our #OS45CEQ), OS150FCE and others. On-board controls are 4 EQ sliders (lo, mid, high & presence), volume knob & low battery light. Powered by 9v battery (not included). Output jack & battery compartment not included. Pickup bar not included. No installation instructions available. NOTE: Pickup bar not available separately. Not recommended for installation on other autoharps. INSTALLATION OF THIS UNIT WILL VOID THE WARRANTY ON ANY NEW AUTOHARP BECAUSE IT REQUIRES EXTENSIVE ROUTING OF THE BODY.