Access potable water anywhere. Convert your reservoir or water bottle into a water filter. The 28mm inline filter sets a new standard for lightweight, fast and versatile backcountry water filtration. Compatible with all HydraPak 28mm opening bottles and flasks, as well as Plug-N-Play connectors used on reservoirs and water storage containers.Avoid freezing filter. Freezing may ruin the hollow fiber membrane. Filter Kit includes:Inline FilterCap Adapter - Plugs into filter outlet allowing user to thread on their Stow or Smart Water™ Bottle cap.Backflush adapter - Plugs into filter outlet and threads onto a HydraPak Stow or bottle of clean water for backflushing the filter in order to restore its flow rate.Product use and care instructions*Effectively removes common waterborne bacteria, such as E. coli (99.9999%), and parasitic cysts (99.999%) per EPA Guide Standards and NSF P231 and microplastics (99.999%) per NSF 42 greater than or equal to 3.0 microns in size.EPA COMPANY NO.:102123EPA ESTABLISHMENT NO.: 102123°CHN°1Weights and DimsDiameter: 34 mm / 1.3 in Weight: 47 g / 1.6 oz (filter only)Length: 129 mm / 5.1 in