Water is heavy enough without adding a weighty pump filter. This minimalist system from Katadyn includes a microfilter and soft-sided bottle combined into one squeezable half-liter unit. Just fill it from any water source, put the lid on, and suck. “Drinking was quick and easy,” says one tester. After a month of testing, we had no problems with silty water in beaver ponds. Other testers said it packed away better than all other filter systems (the whole thing fits in your palm) and still flowed faster. $40; 2 oz.