Bartolini TQB 918 Quad Buffer for Magnetic pickups produces 9V or 18V. The buffer makes everything a little crisper and blends it together to maker a cleaner sound. It is designed to buffer each individual coil in a dual humbucker bass. When you load the coils and pots, you can avoid the high end loss with this buffer. It has a 270ohm input impedance and a low output impedance.