Keep your thermos straws always clean with the Silicone Straw Brush for Thermos Tumbler Zingies SB9. Specifically designed for 9 mm diameter straws, it is ideal for the Zingies Yuki Tumbler, the Zingies Luca Water Bottle, and the Zingies Nico Tumbler, as well as for any other tumbler thermos that uses a straw of the same diameter. With a flexible stainless steel core and a soft outer coating made of 100% silicone, it provides effective cleaning without scratching, helping to easily remove everyday residues from the inside of the straw.