? A TRULY PORTABLE COFFEE MAKER - Simply drop this lightweight 2.8oz Rumble Go filter into a compatible water bottle, and you've instantly transformed it into a portable cold brew coffee maker. The brewing process couldn't be easier: just add coffee grounds to the filter and water to the bottle, then seal it up and give it a "rumble" (i.e. rotate bottle horizontally 2 times), and your coffee is now brewing! By morning, you'll have cold brew coffee as good as the stuff the pros make. ? COLD-BREWING IS THE SIMPLEST WAY TO MAKE COFFEE OUTSIDE YOUR HOME - Now you can make coffee just about anywhere you go, since there's no need for heat or electricity. With Rumble Go you can brew coffee whether you're camping, picnicking, driving, traveling for work or relaxing at the beach. All you need are grounds, lukewarm water and time. Rumble Go takes portable to the extreme. No glass bottles to break. No disposable filters to forget. No fragile parts to protect. No gizmos to charge. ? UNIVERSAL DESIGN HAS AN EXTENDABLE BASE THAT FITS MANY 16-32OZ WIDE MOUTH WATER BOTTLES & INSULATED TUMBLERS - Rumble Go’s universal design features an extendable base that adjusts by up to 1.5” to allow it to fit many of the leading WIDE-mouth water bottle and insulated bottles on the market, including Hydro Flask, Klean Kanteen, Nalgene, CamelBak, Fifty-Fifty, Mira, RTIC and more. See the compatibility list in the image gallery for more info and tips for measuring your own bottle. ? A FILTER DESIGNED FOR STRONGER COLD BREW COFFEE - Stainless steel filter was designed by cold brew experts to make professional-quality coffee. The 18/8 stainless steel filter features 200 micron holes, the ideal size for allowing water to circulate & optimal extraction to occur with coarse-ground coffee. It’s a radical improvement to those first-generation cold-brew kits with fine mesh or paper filters, which were originally designed for brewing hot coffee. You’ll taste the difference. ? DURABLE, ECO-FRIENDLY & DISHWASHER SAFE – The type 304 stainless steel filter is shockingly lightweight (2.8oz incl. cap + base) but sturdy & dent-resistant. The food-grade silicone cap & base are BPA-free and act as shock absorbers protecting your bottle & filter from dings during movement. Eco-conscious design means no disposable filters, no plastic parts and a very minimal packaging footprint. All 3 components can be easily separated for a quick rinse or washing by hand or in a dishwasher.