Formerly sold as Quantum Grills. Coated cast iron grates lay directly on top of the radiant surface which consists of thin stainless steel plates. The grate configuration has changed over the years and many older models, including Quantum models, are still being sold. Whatever version grates you encounter, they get very hot and radiate evenly across the surface. The plates have several small holes per square inch allowing combustion gases up and some drippings down, both good for flavor. Most drippings hit the plates and incinerate, adding more flavor to the meat. On past models, the stainless grates corroded easily and the holes needed regular cleaning or they clogged. We have not yet had a chance to test these new models.
Char-Broil packs a special cleaner/scraper into every box that works specifically with the Commercial grills. Meathead, our founder, bought a Quantum Commercial 4-burner in 2008. After one year the factory grates corroded and clogged so he replaced them with another company's product, GrillGrates, which operate on the same principle, only better. Every year Char-Broil tries to tweak these grates so you may run into older models with slightly different specs.