Quick review of my grayl water filter I did last year. It's a quick and easy to use water purifier that takes out viruses, bacteria, protozoa, and chemicals/heavy metals. It's rare to have a portable device that can remove all of those contaminants. One filter can clean up to 65 gallons. It is bulky and they sell a smaller one called the ultra press. I use it for backpacking, trips to other countries with questionable water, and emergencies. I love mine.

On sale at grayl.com and amazon for 20% off.
https://grayl.com/collections/geopress-filter-purifier/products/24oz-geopress-filter-purifier-water-bottle-nature-editionUsed my Grayl water purifier for the first time in American Samoa. Just used it for tap water for now, which locals recommend not drinking. Might try it on a stream later. You wouldn't normally carry it in the 24hr pack due to it's size. It would be good at Basecamp or places with really bad water.
Positives:
1. Filters it all...viruses, lepto, bacteria, protozoa, chemicals, and heavy metals.
2. Quick and easy to use
3. Charcoal filter removes the bad tastes
Negatives:
1. It's big and heavy
2. Filters have a relatively short life