Those are GrillGrates, they use them for the steak cookoffs. You can order by length and they make custom grates for some models of pits. They're a little pricey but I use them all the time and worth the money. They will also come with that spatula to make flipping easy.
https://www.grillgrate.com/shop-by-length/
This is talking about gas grills but they also work on charcoal.