Reusable Collapsible drink bottle/container. I have a 2 pack, a 3 pack or get all 5!! Put water in them (hot or cold), Gatorade, whatever you need!! These are great and convenient for walks, hikes, camping, whatever you need. After it's empty you can fold it up flat and stick it in ur pack and go!! $15 is for all 5!! Other
ThinkGeek :: Solar Powered Water Bottle Cap --- note from kelly - bought this for my husband and 12 year old son for 2012 christmas. They are awesome and I think they will like them for camping. but definitely check the bottles you have.
Weighing only oz., the Vapur Element 34 fl. water bottle is about the weight of a 32 fl. hard-plastic water bottle and it folds down when empty to take up little space in your pack. Available at REI, Satisfaction Guaranteed.