Water Filter Survival For Backpacking And Emergency Preparedness:, 0.01 Micron. Product Details High-Efficiency Filtration: The water filter straw is made up of 0.01 ?m hollow fiber ultrafiltration membrane, Activated carbon fiber, and double PP Cotton.It filters about 600 milliliters per minute.The entire water filtration system is made of food-grade materials. Easy to Use: Just hang on a tree or put the gravity water bag in a high place, hands-free filtration, enjoy effort-free (no pumping, no squeezing) filtered water within minutes.The operation of this gravity-fed water filtration system is remarkably straightforward. Easy Maintenance: Wide open gravity water bag, water filling and flushing are very fast and convenient. The water filter straw backwash design, Insert a plastic bottle into the outlet of the filter for backwashing, no need for an extra syringe. Multi-scene Application: As a necessity for outdoor water purification, the Burtrail Gravity Water Filter is applicable to camping,hiking,backpacking,emergency preparedness (rainstorms,floods,earthquakes,hurricane,etc.) to meet the emergency water demand in a variety of situations. Portable and Lightweight: No cumbersome fittings and lightweight. Easy carrying survival water filtration system when putting all the parts in the organizer bag. Payment We accept PayPal and credit cards via PayPal. Taxes - US We collect sales tax, as required by law. Shipping We make every effort of shipping within 3 business day of payment clearing. The estimated delivery time is 2 - 5 business days from the shipping date. Policies If you do need to return your item, please contact us via email (you will receive an email when your product ships with additional details - Subject: Important information about your purchase). You will then be provided with a return shipping label and packing slip. Pack the item carefully. Include the packing slip, apply the shipping label, and return the item within 30 business days of the date you request a return, or your return will be canceled. Once we receive your order we will inspect the return. Please allow up to 5 business days of receiving the returned item for your refund.