Outstanding item. These weigh less than the rigid LDPE/HDPE bottles and they can adapt a bit to the available space within ones backpack. The cap is attached with a small bail to prevent loss. Lastly - and best of all - when the canteens are empty, they may be rolled up to occupy almost no space. These canteens are surprisingly durable. I have never experienced a leak.
This review was written in the old system and had content requirements that are different than reviews written today.