(a) Built-in Temperature Recorder (Partlow) - The temperature recording device that is part of a reefer container cooling equipment. During transit, the temperature of the air coming out of the cooling equipment, before it enters the cargo container, is continuously recorded on a round chart, i.e. the Partlow chart. As the equipment cycles on and off (just like a home refrigerator) peaks and valleys are produced on the chart as the output is recorded. The chart is in the possession of the carrier before, during, and after the voyage. (b) Portable Temperature Recorder (RYAN, COX and other brands) - A battery powered self-contained temperature recording device that is independent of a reefer container cooling equipment. One or more units are placed in a container (usually by the supplier) when the cargo is loaded. During transit, the temperature of the air inside the cargo container is continuously recorded on a roll of paper, e.g. the Ryan tape. When the cargo is unloaded at its final destination, the unit is removed by the consignee, who usually opens the unit and removes the tape. The unit can be sent to the manufacturer for testing and authentication of its accuracy