All four PDU categories are available in low- and high-voltage versions to satisfy the power needs of all applications worldwide. Models in two categories (Basic and Metered) are available with Single-Phase input only. Models in the other two categories (Monitored and Switched) are available with either Single- or 3-Phase input. Basic PDUs (available in Single-Phase input only) provide enough outlets to reliably run the many networking, server and telecom loads that require continuous power. Metered PDUs (available in Single-Phase input only) allow managers to locally view the total load in amps on the PDU. This allows managers to keep track of the amount of power the equipment is consuming, helping to prevent overloads and determine when to apply more electrical capacity or larger UPS systems to support the growing network. Monitored PDUs (available in either Single-Phase or 3-Phase input) allow managers to remotely view the total load in amps on the PDU (as well as user-defined PDU alarm conditions) using a built-in network interface. This allows managers to take more proactive steps to prevent overload and ensure continuous availability. Switched PDUs (available in either Single-Phase or 3-Phase input) allow managers to remotely control locked devices by temporarily cycling power off and back on again, eliminating the need to travel to remote sites for a manual reboot. Specialty PDUs include "Hot-Swap" models (which ensure continuous power availability when a UPS system connected on the input is removed for maintenance), ATS models (which provide automatic transfer switching), and models with two separate power circuits to support redundant power applications.