The SimPure brand Gravity Water System comprises a 3 litre capacity themoplastic polyurethane water storage bag, a silicone drain/feed tube with shut off clamp, a water filter straw with an outer body made of acrylonitrile butadiene styrene, a screw on bottle interface made from polypropylene, a slide-on handle/clip,a metal carabiner (clip), a textile hanging strap and PVC coated textile pouch. It is designed to filter stored fresh water collected from streams, rivers or lakes for example. On its own, the straw can be used to drink water directly from the surface. The straw uses a combination of a coarse pre-filter, a 0.1micron hollow fibre ultrafiltration membrane, a 5 micron coconut shell granular activated carbon filter, and a 0.2 micon polypropylene fiber fitler that is designed to remove heavy metals, chlorine odours and microplastics. Over its life, the straw can provide up to 1500 litres of drinking water at a flow rate of 27 litres per hour, effectively removing dirt, parasites, viruses and bacteria etc. to provide clean, safe drinking water. Measurement given is for the straw only.