This is great for the minority of us who prefer to upright filter as we drink - like drinking out of a glass with a straw and sucking, rather than tipping the entire apparatus upside down and squeezing. For this to work, you need a container that is both squeezable and that has variable volume, meaning most bottles don't work. The original sacks that come with the Sawyer filters have these properties and are ultralight, but they are floppy and lack durability. For a little extra weight the Vesica largely solves these problems - it goes into my pack pockets easier, and when it's mostly full it's rigid enough not to let my filter flop around. When it's less full I can tuck the top into my pack pocket which also stops the filter from flopping.
Love it!
A wonderful alternative to the Smart water bottle.
Update: i used this on a long hike and it was difficult to get into my shoulder strap bottle holder. Im not a fan.
It does what it says it’s meant to do. It takes up less space when empty rather than taking up the same.
Awesome!