Hewlett Packard 40Amp High Voltage Core Only Corded PDU Modular 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. Single phase models are available up to 40 amps and can have up to 28 outlets divided across 4 extension bars