Material: Our straw cleaning brushes are made of stainless steel and durable food grade nylon bristles,which are not easy to fall, and they will not damage the surface of bottles. Application: These bottle cleaning brush set are suitable for cleaning bottles, drinking straws, coffee machines, kettle teapot spouts, drinking straws, keyboards, etc. Efficient Cleaning: Different size brushes for different place cleaning, easy to get into hard-to-reach spaces, and scrub away any food, dirt or any stains without damaging whatever you are cleaning. Unique Key Ring Design: The brushes come with a detachable key ring that you can divide or put them together quickly according to your different needs. And with this key ring, you don't need to worry about losing them. Multiple Size - We provide a package of 10 nylon bottle cleaning brushes with different diameters to meet different place cleaning needs: 2mm, 3mm, 4mm, 5mm, 6mm, 8mm, 12mm, 16mm, 20mm, and 24 mm, and overall length of all brushes are 21 cm.