Rumble Go could be the world's most portable coffee maker. Just drop the Rumble Go filter into a compatible water bottle, and it's instantly transformed into a portable cold brew coffee maker that you can take anywhere. The brewing process couldn't be easier: just add coffee grounds and water and give it a "rumble", and your coffee is now brewing! See the brewing steps here The universal, extendable filter is compatible with a range of popular 16-32oz WIDE-mouth water bottles, such as Nalgene®, Hydro Flask®, Klean Kanteen® and CamelBak®. See a list of compatible bottles (or view the chart in the image gallery). Includes:  + 18/8 Stainless Steel Filter, Specifically Designed for Cold Brew  + Food-Grade Silicone Cap & Extendable Base (available in 2 colors: Orangey-Red and Dark Black)