When testing the aging of electronics by means of increased temperature, it is essential to ensure that the temperature is distributed as evenly as possible over the test object or the test samples. If the temperature is unevenly distributed by only a few degrees Celsius, this can very grossly falsify the service life evaluation. Our Burn In oven has been specially optimized for this distribution. With commercially available industrial furnaces, there is often the problem of achieving an even distribution of heat. Usually, this is due to the airlock through which the measuring lines are led from the furnace to the test electronics. This problem is solved by our special design of the back wall of the oven. Signals, supply lines, etc. are passed through the back wall without affecting the temperature gradient.