Last year I bought an AWT fan oven, which is fine, except that it only comes with one oven shelf!
I bought an extra adjustable one, and when I was planning a large party for Christmas, I decided I would buy another. I chose this one as I wanted quick delivery.
It fills the bill perfectly. It is easier to adjust than the other one I bought - just a simple slide out action. For doing several trays of party food for large numbers, 3 shelves were invaluable, and I might even buy another one.
The added advantage is, being adjustable, I could lend them to friends if they want to invite me to a party!