Reefer

A Reefer is a refrigerated ISO shipping container with self-contained refrigeration machinery, used to transport temperature-sensitive cargo — fresh produce, frozen foods, pharmaceuticals, dairy, meat. Standard sizes are 20'/40' (and 40'HC), with the machinery occupying one end of the container.

Reefer containers require electrical power to maintain temperature: at sea, they're plugged into the vessel's reefer sockets; in port and on rail/road, they need power generators or genset attachments. Temperature is set in advance (set-point), and most reefers can log internal conditions for the entire transit.

Commercial considerations: reefers cost 3-4x dry container freight per slot; they generate continuous demurrage if dwell time exceeds free time (refrigeration costs power); and they have higher detention rates because empty reefers are scarcer than dry containers.