Perfect for your hiking adventure, big or small. Easy to use, brew on the go! Use it at the campground, local watering hole, or during your travels where glass is not as welcomed. When you aren't brewing, enjoy your bottle for any use! Fits wide mouth water bottles: Nalgene, Hydroflask, Klean Kanteen, etc. 1/pk Reusable organic cotton coffee filter made to fit 32 ounce wide mouth bottle - CoffeeSock ColdBrew filters are durable and may last a year or more. CoffeeSock ColdBrew filters are a reusable alternative to paper filters and nylon sacks. All of our filters out-perform any comparable disposable and reusable filters. Cotton absorbs some of the oils released from coffee beans yet lets acids pass through.