Check brush head size before buying: With its 12.5" long non-flexible steel shaft and sturdy 2" silicone head, our water bottle brush penetrates deep into tall, narrow containers such as insulated water bottles, bottles, vases and thin glassware Directions: Since silicone is not absorbent, it cannot not foam like a sponge. For best results when using our bottle brush, simply add warm soapy water to your container and then scrub. The minimum neck diameter the brush will squeeze into is 1.5" wide, so it is not suitable for cleaning beer, wine or kombucha bottles. A BETTER HYGIENE FOR YOU: Our silicone water bottle cleaner repels unpleasant odors and stains, unlike sponge and nylon brushes that fall off and release an odor after a few uses. This scrub brush prevents nasty dirt build-up, which is more hygienic and healthier for your family No more scratches: the easy-to-clean, scratch-resistant silicone bristles of our cleaning brush 12.5" long bottle caps are smudge-proof, yet soft enough to leave your vase, glass water bottle, pitcher, blender, and delicate glassware clean and scratch-free. Say goodbye to mess GROSS CONTAINERS: It's great as a sports bottle cleaning brush, for ejecting goo from your bottle, scrubbing soup from your thermos, or making residue in your baby bottle. Our 12.5" long bottle brush is also perfect as a travel brush Durable and long lasting: The strong bristles of the sturdy cleaning brushes will hold their shape, and won't break or fall off not. Our long bottle brush fits bottle necks 1.5 inches or wider, and is heat resistant up to 400 degrees Fahrenheit.