Squeeze-bottle filters are handy for travelers and day hikers who don't need to treat large volumes of water. Take one as a backup for a pump filter, or skip the pump if all you want is a bit of refreshment on the run. Be warned, though: Since bottle-style units rely on squeezing rather than high-leverage pumping, these babies are slooow. Plus, none of them kill viruses. None, that is, except the eight-ounce Exstream shown here. It requires a very firm hand to force water through its angled nozzle, but there's solace in that: The slow flow rate gives your water dwell time in a cartridge of iodinated resin, meaning evil viruses go bye-bye. It's great for travels in Third World countries and dip-and-sip drinking from a canoe.