These IEC power cords are recommended for PDUs, servers, and UPSs. The supply end hard-wires directly into your device, while the female end connects to any device or appliance that has an IEC-60320-C20 inlet. The Auto-Lock C19 is an internal mechanism that holds the pins of the C20 Plug or Inlet to keep your device from being accidentally unplugged! These components are sturdy yet unplug with ease whenever you want to remove the power cord!