Herb Keeper is made of polypropylene and is ideal for large bundles of herbs. Designed to create an ideal storing environment to help extend the life of fresh herbs. Simply fill base with water to fill line and place cut herbs in the basket. Basket keeps delicate leaves off of container walls and promotes air flow to prevent rotting. Lid keeps humidity levels high to prevent herbs from wilting. Slim profile for fridge door storage. Dishwasher safe.