Accessories for Diercon Mini water purifier straw : Extension Tube, Foldable water bag, Backwash device & a Pre-filter. ONLY TO BE BOUGHT ALONG WITH THE DIERCON MINI WATER PURIFIER STRAW Foldable water bag to carry water or suck water from Pre-filter for additional filtering Backwash device to clean the filter after every trip Extension tube makes water sucking from a distance easy