The one indispensable item that I always carry is my Sterilight Adventurer water purifier. No waiting for boiled water to cool, no bad taste. Just stick the wand in the water and a UV light comes on for 90 seconds. It will flash green if it was successful (the light on the pen, not the water flashing green...lol). I use a solar recharger to make sure it stays charged. Some of my best spent money. Caution, the water must be clear for the purifier to work, otherwise you must filter it before treating it.