ART PB 4x4 Rackmount Power Distribution SystemPB 4x4 features ART's "4x4" distribution on the back of the unit four of the eight rear outputs are 1. 25 inches apart. This allows the user to plug in wide power cables and multiple wall wart devices, and still have eight total power outlets to choose from. Built into the PB 4x4 is a Surge and Spike Protection System, designed to protect powered equipment from harmful electric surges and spikes. The unit also has RFI and EMI filtering. The PB 4x4