The cooking plates of the OFYR cooking units run slightly downward towards the centre. When the cooking plates are heated the centre will drop a little further down. The result is that around food such as tomatoes but also very fatty food can roll or slide to the centre of the cooking plate & fall into the fire. The raised steel rim stops the food but still offers the possibility to scrape the cooking plate clean with the spatula & push the scrape under the rim into the fire. Made from coated steel.