These glass straws, which are hand made, are very strong and have bumps (either blue, green or red) so that they don't roll off the table. The diameter on these glass straws is 12 mm. 9" long. They are wonderful to use and this diameter works well for smoothies. Dishwasher safe. If any food material gets in them, then you need to either rinse the straw quickly or use the cleaning brush. Lifetime warranty by manufacturer under normal usage. Eco categories: Reuse, less toxic.