Manufactured with medical grade polystyrene plastic, these trays are numbered and color coded for quick identification. Each tray features ergonomically contoured edges designed for maximum patient comfort, Rim-Lock Edge system for secure alginate retention and inner support tabs for extra grip support. Each tray also features convenient hanging tab holes that make organizing and storing a breeze. Upper and Lower available in 6 sizes. Single Pack: 50 Trays Per Package (Upper or Lower). Assorted Pack: 60 Trays Per Package (Upper AND Lower).