The PLB2X8 Dual Loadbox from Palmer is designed as a substitute for a speaker and ensures that your tube amps are connected to the correct load on the output, minimizing the risk of possible amplifier damage. The Dual Loadbox can also be used with guitar amps that have a line out or filter out connection. This is achieved through silent operation of the amplifier with simultaneous use of the line/filter output. The dual-channel and strictly reactive loadbox pairs well with speaker simulators that do not have built-in load. The loadbox is constructed of strong and durable powder-coated sheet steel.