0.4 in Straw Cover compatible with Hydroflask Tumbler 40 oz & 32oz: This straw cover cap is suitable for all types of straws with an outer diameter of 10 mm, perfectly compatible with hydro flask all around travel tumbler with handle 32 oz and 40 oz. Essential Accessory compatible with Hydro Flask Travel Tumbler: The tumbler straw cover seals the straw and keeps away from dust and impurity. Our straw caps are small in shape and portable. They can prevent water from spilling when you move. Especially suitable for camping, walking and other outdoor activities. Made of 100% Food Grade Silicone Material: Our silicone straw tips are carefully made of safe silicone, durable and reusable. No odor. Diverse Straw Cap Cover: Compared with other single style products, our tumbler silicone straw cover caps come in 3 different designs and 4 colors. There are 6 pcs straw toppers in total, which means more options for you. Value Pack: Comes with 6 PCS straw covers compatible with hydroflask. You can share them with your friends or family. Easy to install. Even if the straw protector is open, it can easily hang on the side of the straw and won't be lost. Please note the straws are not included.