MPDU 24A 208V 3PH PDU HP Modular PDUs have a unique modular architecture designed specifically for data center customers who want to maximize power distribution and space efficiencies in the rack. Modular PDUs consist of two building blocks - the Control Unit (core) and the Extension Bar(s) (sticks). The Control Unit is 1U/0U, and the Extension Bars mount directly to the frame of the rack in multiple locations.