Key Features: 1. FILTER MORE: Filters up to 4000 liters of natural water without using any chemicals. 4000L clean and drinkable water in a backpack . 2. VERSATILE DESIGN: set up a DIY filtration system by soda bottle like bottle, plastic bag, collapsible bottle or bucket. Or drink directly from water source like a straw. 3. BACKFLUSHING WITH EASE: Threads on filter both sides. A 28mm threads bottle can be screwed on water filter outlet for backwashing. Good for camping, hiking, fishing, scouting, travel, , use, or emergence supplies. color: Blue Material: ABS Package Contents: 1 x Water Straw Filter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.