A:AnswerThis is a single wall oven. If you are referencing the interior, we design our ovens with high quality materials that can handle the heat produced. Multiple layers are used within the the cavity.
A:AnswerGreat news! The Air Fry feature doesn't require any preheat time. There are multiple factors that can attribute to the preheat time, such as room temperature, the starting temperature of the oven, and the number of racks inside. However, due to the hidden bake element the average preheat time to 350°F for this model is 15-20 minutes. Joyce@GEAppliances
A:AnswerThis oven certainly does have a temperature probe! If you'd like, you can view more on this on page 15 of the Use and Care manual on the product page. -Kacie@GEAppliances
A:AnswerYes, you absolutely would be able to install a microwave/convection oven on top of a single wall oven. As long as you make sure the dimensions match up.