I used to be a research chemist and I developed water purification membranes--I don't believe their claims.

As EMPnotImplyNuclear said, I don't believe it will remove viruses and the device is not big enough to have enough charcoal to remove much soluble contaminates. The water needs to move slowly across the charcoal to have enough time for the contaminates to adhere to the charcoal. And you have to have enough volume of charcoal to contain all the contaminates. Finally, charcoal does not remove all types of soluble contaminates including salts.

Also, membrane filters plug up rather quickly with insoluble contaminates. My company also developed special configuration filters to reduce plugging. This requires flowing the water across the filter as it is passing through it. Continuous cross-flow reduces the amount of contaminates sticking to the surface of the filter. However, this filter works by forcing all the contaminates onto the filter with no cross flow, thus the filter is going to plug up very quickly.

Small filters like this also suffer from cross-contamination. Notice in the video when he is drinking from the device, water on the outside of the bottle is dripping down on his face. This is the contaminated water from the source. If the source is only contaminated with minor amounts of chemicals this is not a big issue, but if it is contaminated with bacteria or viruses, then you can easily ingest the very organisms you are trying to avoid.

None of the technology they are using is new. I was working with all this technology 30 years ago.