polypropylene, virtually unbreakable, dishwasher safe, can be used between -20C and +120C, usable in microwave ovens, with grip hole, stackable * Fits Wood & Sons 9"" NHS plate, Churchill 9"" Nova and Classic plate + Steelite 9" Slimline plate, ** Fits Dudson 9" NHS plate *** Fits on Churchill 10" Classic + Nova plates