A reefer (refrigerated) container maintains a set temperature throughout transit using an onboard power unit, plugged into the vessel's electrical supply at sea and into a genset or shore power during trucking and port dwell. Getting the shipment right depends on more than picking a temperature — airflow setting, humidity control and the product's own respiration (for anything organic) all need to match what the cargo actually requires.
Most reefer cargo from China in a general import context is not fresh produce but temperature-sensitive manufactured goods — certain cosmetics, some electronics components, pharmaceuticals and specific chemicals — where the concern is preventing degradation from heat exposure during a multi-week transit, not maintaining a precise cold chain for perishables.
Continuous power is the operational constraint that matters most. A reefer container loses its controlled environment the moment it is disconnected from power, so every leg of the journey — factory to port, port dwell before loading, the vessel itself, and the final delivery leg — needs a genset or shore connection confirmed in advance, not assumed.
We flag reefer requirements early in the quote process specifically because the equipment and power availability need to be booked ahead, unlike a standard dry container which is rarely the constraint.