The HP Modular Distribution PDUs have a unique modular architecture designed specifically for the dense data center customers who want to maximize their power distribution and space efficiencies in the rack. This design consists of two main building blocks, the Control Unit and the Extension Bar(s). These each PDU unit comes with one Control Unit and up to four Extension Bars. This PDU providing easy accessibility and reduced cable clutter, the PDU offer you the flexibility to easily mount your units in several different locations within the rack, without having to sacrifice valuable rack U-space.