Perfectly compatible: This straw cover is specifically designed for Stanley cup straws. It is perfectly compatible with Stanley 30 oz and 40 oz tumblers with handle straws. Food-grade silicone material: Made from BPA-free food-grade silicone, this straw cover has no unpleasant odor, ensuring safe and worry-free use. It is easy to clean and maintain. Leak-proof and hygienic: The cover helps protect the straw from dust and airborne particles, maintaining cleanliness and hygiene. It also helps prevent insects from entering the cup. Precise fit: Designed to fit Stanley straws with a diameter of 9–10 mm (0.35–0.4 inches). Reusable and dust-proof: Durable and reusable, this straw cover is convenient to put on and remove. It provides reliable protection and is a practical accessory for drinkware enthusiasts. Package: A thoughtful and cute accessory, ideal as a gift for those who enjoy premium drinkware. Features reliable quality and simple functionality.