Abstract: A self-contained cooler/freezer apparatus for carrying items in a frozen or refrigerated environment. The apparatus comprises an insulated container which is divided into two portions. The first portion is utilized for item storage and the second portion houses a pressurized coolant compartment for storing a solid coolant; namely, solid carbon dioxide or dry ice. The pressurized coolant compartment comprises removable insulation panel. These insulations panels are utilized to control the rate of heat transfer from the first portion to the dry ice within the pressurized coolant compartment. Based upon number of factors including desired temperature, storage duration, total item weight, the quantity of dry ice and the number of removable insulation panels can be determined. In essence, the pressurized coolant compartment is a controllable heat sink. Within a short period of time, the dry ice starts to sublimate, thereby forming cold gaseous carbon dioxide at a high pressure.