These are great for reducing the plastic in your life and the landfill. People should not give these a low rating because they don't fit their water bottle or mug. They're meant for 40 oz Stanley-type mugs. You CAN use them in a 32 oz mug, but the straw is going to stick up higher. I use them in both. Because of differing mug heights, regardless of how many ounces they hold, it's best to just measure how tall the bottle or mug is you'll be using it with and go with that, vs capacity. The accompanying cleaning brush it comes with works, fits fine and is a helpful addition. My only complaint is that I wish they'd been sold in a set of two. I don't need four straws, but if you do, these offer the best value.