Survivor Filter PRO Replacement Cotton Filter. We have replaced this with the Backwashable 100, 000 Liter Pre-Filter. OFFICIAL Replacement Cotton Filter for Survivor Filter PRO Outdoor Water Filter Model. EASY TO REPLACE: Simply remove used Cotton Filter and replace with the new one ! BEWARE of IMITATIONS: Use only Official Survivor Filter replacement filters to keep your Survivor Filter Triple Filtration Water Filter Straw in top condition. All Survivor Filter products are shipped from North America. Beware of Foreign Immitation Sellers Shipping from Countries Outside North America.