Material: The brush has a stainless steel handle with a nylon head, offering rust resistance. The nylon bristles clear impurities inside test tubes without damaging the container. Size and set: 10 brushes in total. 5 pieces are 23 cm long with a head length of about 5.5 cm. Another 5 pieces are 20 cm long with a head length of about 5.5 cm. Scope of application: Primarily designed for narrow tubes, test tubes, straws and glassware. Selection: Two length options allow you to choose a brush that fits different tube lengths. Benefits and performance: - Effective cleaning of residues inside small-diameter tubes without scratching surfaces. - Rust-resistant stainless steel construction with nylon bristles for safe, durable use. - Long reach facilitates cleaning hard-to-access areas while minimizing handling of hazardous materials. Use scenarios: - In the laboratory, clean narrow test tubes and small glassware after experiments. - In kitchens or dining settings, clean drinking straws and other slender glassware. - In hobby or workshop tasks, clean narrow tubing and small-diameter glass pieces.