Flasks & Water Bottles
Take a re-fillable water bottle with you on your travels to help stop the massive problem of piles and piles of rubbish acculumating around the world. Platypus bottles and Hosers are considerably more compact than anything else on the market. When walking, use a Hoser so that you drink more fluid and stay better hydrated. Rigid bottles i.e. Siggs and Nalgene bottles can be used as hot water bottles to heat your sleeping bag.
Small Flask: Lovely hot tea, hot juice, hot soup… nothing can make you feel better at the top of the mountain when you are cold than a lovely cup of hot liquid. Remember to warm the flask with hot water first.