The ZVL is a multi amplifier synching module designed to allow a user to link, strap, and tune the preamps of multiple amplifiers from a single module for precision control of large mobile audio systems. The ZVL was designed to work seamlessly with the Z12000, SS2000 and new M Series amplifiers using the ZVL INPUT, but it is universally compatible and will work with discontinued DM Series amps as well as other brands of amplifiers.