Abstract: An insulated container for maintaining a product at a specific constant temperature during shipping or storage using two constant temperature coolants of different temperatures on either side of a highly conductive product storage box to establish a temperature gradient. Two pieces of insulated material of different thicknesses are placed between the product storage box and the constant temperature coolants. The selected thicknesses of the insulated material determine the specific temperature of the product, which will be between the temperatures of the two constant temperature coolants. U-shaped heat equalizers are disposed around the insulated material to conduct ambient heat leakage directly to the coolants and thereby help to insure a uniform temperature throughout the product storage box.