We LOVED these bottles. Why? Oh, I'm so glad you asked!
- they collapse and roll up really small when empty
- they can be partially collapsed as the water is drunk, taking up less space in your pack
- they weigh only 27g/1oz (Kathmandu ones)
- they can be filled even with boiling water
- even though they flatten when empty, the gusseted base means they can stand up when full
- ours had a sports pop-top you can drink straight out of
- they're made of strong, durable plastic.
We used them to carry extra water around with us each day, as a backup for when our individual water bottles were empty. Because they're strong, we could just put them in the backpack with all our other stuff. We also left them in the car if we knew we'd be coming back to it through the day.
We boiled water each night and poured it straight in to let it cool down. On a previous trip, we didn't take bottles that we could pour boiling water into, which meant that we had to pour it into our bowls and let it cool down like that. Pouring it straight into the bottles meant that we didn't have to worry about it spilling (especially as it could easily scald). We could leave the bottles out overnight to cool, or if we had a fridge, we could put them in there so that we had chilled water.
The water tasted fine, and didn't have a plasticy flavour at all. We had no problem with leaks, and I've even heard of people filling them up with hot water, putting some fabric around them, and using them as makeshift hot water bottles to keep themselves warm! Not a bad idea!
I highly recommend collapsible water bottles (Platypus brand shown left) for travelling with kids. It just meant that we didn't have to worry about running out of water on our daily tripping about, and when we didn't need them, they could be rolled up so wonderfully small. We saved money because we didn't have to buy bottled water. There's nothing like saving money, worry and effort for enjoying travel with kids!
Of course, you don't have to only use them for travel - they can be used any time!