These are the simplest version of our glass straws, which are hand made and very strong. The diameter on these glass straws is 9.5 mm. 9" long. They are wonderful to use and this diameter works well for most uses (use the 12mm diameter for smoothies). If the straws might be left on a surface then the bent or bumps versions should be used to avoid having the straw fall. 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.