I didn't know it had this feature until reading the booklet. But it's my favorite! No need to open up the door to check the food. 
I am very happy with the range and the air fryer. 
Th only thing I dislike and the reason for 4 stars, is the bottom drawer. It is poorly designed and made. Very cheap looking and not a solid piece. It bends and warps. And it's extremely hard to pull out and push in. Poor quality in that aspect of the design.