Katadyn Gravity Water Filter

From the Amazon Listing

• 5-Stage Efficient Filtration: With adoption of premium-quality 0.1 um ultrafiltration membrane and other raw materials, the Water Filter Straw can effectively reduce harmful substances like chlorine, particulates, sediment, stones, sand, dirt, bad taste &odor in water to ensure the water safety and deliver better drinking experience.
• Professional Combination: Waterdrop Gravity Water Filter Straw with 1.5 gal Gravity-Fed Water Bag is an exclusive water purification combination created for outdoor activities and first aid survival. The large-capacity water bag can hold up to 1.5 Gallons of water at a time, which is about 11 bottles of 500 ml bottled purified water, and can meet the all-day demand for outdoor water drinking.
• Longer Lifespan: The Waterdrop Filter straw can provide safe drinking water up to 1,400 gallons (5,300 liters), and ensures the maximum water flow rate of up to 700 ml/min to provide more relaxed outdoor water drinking experience.
• Recyclable Straw: With innovative backwash purifier function, the inside of the Water Filter Straw can be kept clean at all times and it is recyclable, safe and pollution-free. If the water flow decreases or the filter has been used for a long time, you can remove the mouthpiece, flush it with clean water. (Standard water bag can be used or pop bottle with thread diameter of 27.5mm can be filled clean water for backwashing the filter straw.)
• Versatile Uses: The Water Filter Straw can be connected with water bags or water bottles to filter water for drinking. Both ends of it can be disassembled and connected with the water bags and the water bottles to offer you clean drinking water anytime anywhere.