Both the 8-litre gravity and 8-litre storage bags are completely leak-proof for mobility. The Safe Water storage bag has a special screw spout for quick pouring and a hose connection for added functionality and versatility. You can even remove the filter from the gravity pouch and use it as a straw on the go, connect it to a water bottle or use the included stopper to stop the flow and use it as a second storage system. The 0.2 micron filter size filters 99.999999 of bacteria, 99.999% parasites and as much microplastic. The water storage bag is made of high quality materials , BPA free (without plastic softeners), which ensure a long life. Improved micro-filter performance: the redesigned membrane and special backwash accessories provide better performance against sand and silt and maintain flow for a long time. The membrane microfilter lasts up to 2000 litres. Included: LifeStraw Peak Series 8L gravity bag with hose and standard quick connect, carabiner, leak proof water storage cap, single carry strap, LifeStraw Peak Series 8L secure water storage bag, twist lock, backwash accessories, user manual. And, your purchase has an impact: 1 purchase = 1 year of clean water for a child (doing good programme by LifeStraw).