Cork is an impermeable, buoyant material comprised of bark tissue that has been harvested and refined for commercial use. The small cork stoppers in this Hillman assortment have a tapered shape to provide a secure seal in various-sized containers. The natural cork construction can be cut to an exact length, and its natural elasticity helps form a tight seal. Commonly used as bottle stoppers. Full assortments of #52000 feature Hillman item numbers #52001 - 52008.