This individual, multi-applicable lid is designed to securely snap to your AlumniMold tray(s), sold separately, to keep your castings secure and clean of contaminants or odors during casting or storage. Measuring at 6.5" long, 4.5" wide, and 0.5" tall and made of the same food grade safe silicone as the AlumnniMolds trays, the lid is durable, versatile, and safe to use across the freezer, oven, and dishwasher to meet your casting needs.