STURDIEST BRISTLES - 0.01 inches(0.15 mm) thicker diameter food grade nylon bristles, medium-soft yet with added scraping efficiency STURDIEST ROD - 1/8 inch thick spiral strong double rod of Food Grade Stainless Steel 304, for extended durability. The thinnest brush of the set has a thinner, more flexible rod ERGONOMIC HANDLES The simple ergonomic design of the Buenalife proprietary handle design improves grip and torque and can be easily hanged in kitchen or workshop hangers REUSABLE & DISH WASHER SAFE - Long durability. Can be washed either manually or in any dishwashing machine MULTI-PURPOSE - Many different uses apart from reusable straw cleaner brush(plastic, metal, silicone, bamboo). Other uses include cleaning small bottles, food processor and various kitchen appliances parts, test tubes, funnel necks, small plumbing pipes and other hard to access corners, precision tools, tea pot or coffee pots, sippy cup medicine dispenser, perculator, cpap tubes, glass pipes. Can also be used for various tumblers like Yeti, Tervis, Rtic, Bubba, Ozark, Klean Kanteen. Buenalife Heavy Duty Cleaning Brushes Set of 4 - Extra Long Straw Cleaners for Metal and Plastic Reusable Drinking Straws, to Clean Small Spaces, Sippy Cups, Water Bottles - Sturdy Hard Brush Bristles