Material: Stainless steel stem with durable nylon bristles ensures long-lasting use and gentle cleaning. Sizes: Small (17.5x3x0.5cm), Medium (20x5x1cm), and Large (20x5x1.5cm) fit various tube and bottle diameters. Packaging: Available in 5, 10, 30, or 50 pieces to accommodate different usage frequencies. Design: Flexible double-ended brush with dense bristles reaches tight corners and cleans effectively without scratching surfaces. Usage: Works for cleaning straws, water bottles, milk bottles, test tubes, teapot spouts, coffee machines, hummingbird feeders, sink pipes, aquarium filters, and more.