Platypus  DayCap In-Bottle Filter

So I read the two reviews and took a chance using my dividend. Bought it, walked to my rental car and installed it on a hydroflask trail series full of water. Then I shook it… and shook it… and shook it. Then, since it wasn’t leaking I dropped it from stomach height onto pavement. New dent on my bottle, but No leaks. Then tossed it in the back and drove to my hotel… still no leaks. Laid it on the desk in the room upside down for over an hour…. No leaks. The function seems pretty legit to me.

As a guide, I spend long days in high altitudes, often relying on rivers, streams, or glacial lagoons for water. In places like the “Nido de Cóndores” camp on Aconcagua, I’ve seen many climbers struggle with stomach issues after drinking untreated water from the frozen lagoon. Having the DayCap™ In-Bottle Filter makes a huge difference—it allows me to stay healthy, energized, and focused on what truly matters: reaching the summit and supporting my team. The best part is that it doesn’t add extra bulk or weight, since I already carry a bottle. It’s all gain, especially for my health and performance in the mountains. A simple, reliable solution that I now consider essential.

The first time I filled up my bottle with this in-bottle filter I placed the bottle in the side pocket of my backpack and laid the backpack on its side while waiting for a flight. When I grabbed the bottle 20 minutes later to take a drink the side of my backpack was wet. I held the bottle upside down and drops steadily flowed out from the lid even though it was snapped fully shut. Works fine if you keep it upright. Great idea for a filter and maybe I just purchased a damaged unit but I will be returning it. Disappointed to find out it leaks as I leave for a trip where I needed a filter.

I bought this because I don’t always have access to the best water. That being said this filter is fantastic, most of the time all I can taste is cold there is no flavor or smell to the water. It takes about 10 32 oz nalgenes for the filter to fully break in and allow full flow but after that you’re good. It took about a day and a half. Just hydrate and it’ll be fine! Works fantastic.

This is a good day hiking filter, where you’ll just be filling it and drinking (only very light suction is needed to pull water through the filter. This is not a good backpacking filter because it’s very difficult to filter from one container to another (for example, into a cook pot), and impossible to do so from a hard-sided container like a Nalgene Tristan bottle. It’spossible to squeeze water through the filter on a Nalgene “ultralight” polyethylene bottle, or even an MSR Dromlite reservoir, but it’s a slow, awkward process.

Used at Mt. Rainier recently catching stream water. Easy universal screw on top. Tethered cap. Convenient grab handle. Water tastes great. Water easily suctions out. Sturdy and well built. Look forward to beating the heck out of this strong plastic cap.

I like to use this while traveling to countries where the water may be suspect. I want to avoid buying bottled water and creating more landfill. Will likely also use when hiking/backpacking so that I can fill up at a stream. Initially I noticed a bit of a plastic taste but I don't notice that anymore.

Saw this on social media and had to buy one! Just used it this past weekend while climbing on a hot day. Filled up my bottle in a little stream while hiking back and instantly had fresh, cold water! Highly recommend!

Filters well, easy to drink. Was great for two hikes and now it leaks everywhere if it’s not perfectly sitting up. Very useless for travel when it’s leaking all over the plane, car, in your bag etc.

Glad someone finally made a product that was compatible with other manufacturer's wide-mouth bottles! This is great for day hiking and cutting down on the after you need to carry. Very easy to use.