The platypus gravityworks 2 litre water filter is an easy to use high capacity filtration and water storage system that delivers filtered water at a fantastic rate of 1 5 litres a minute making it a fantastic filtration system to take with you on a group expedition the gravityworks 2 litre water filter system comes with a dirty reservoir hollow fibre filter hoses and universal bottle adapter the dirty reservoir has a zip opening to easily collect water and the follow fibre filter quickly and eas