Food cover has multiple uses - it can be flipped over to rinse produce or strain pasta, and is used to keep bugs off food. Condiments are substances like relish, vinegar or spices that flavor or complement food. Flat servers are round or wedge-shaped utensils, some with shallow bowls, used to balance sliced food when transferring from platter to plate. Dinner plates are the most commonly used plates, serving the main course at formal and informal meals. Trays are shallow platforms for carrying items, and napkin holders are devices that hold napkins without allowing them to slip free.