The BeFree Flask is made of very stretchy plastic that allows the user to squeeze the water through the filter by squeezing the flask. At the same time, it takes up very little space and, unlike a hard plastic bottle, can be folded up and stored economically.
Transporting the filled flask in a backpack can result in a damaged flask. Although the material is stretchy, the movement of objects in the backpack can put pressure on the flask during transport. The best way to repair such a hole/tear is to use a self-adhesive Velo patch, which is also stretchy and stays stuck for a long time.