Katadyn Gravity BeFree 3L
This collapsible 3L BeFree flask hangs (with included straps) so gravity pulls water down the tube. No work! It will filter out the nasties (except viruses) and particulate, and to clean the filter you simply swish water around in the flask. 100% BPA and PVC free.
Weight: 192 g
Filter: 0.1 micron hollow fiber
Effective against (99.99%): bacteria and cysts
Output: up to 2L per minute
Filter life: up to 1000 L