ADVANCED AND SAFE TECHNOLOGY: With Membrane Solutionss advanced safety filtration membrane technology, this filter straw is divided into four stages, including coarse filter screen, Polypropylene nonwovens, coconut shell activated carbon and hollow fiber ultrafiltration membranes. It is able to remove all visible solid sediments,reduce 99.99999% of harmful substances, and improve the odor, ensuring the safest water in the worst environments. PORTABLE: This straw filtration at only 6.7” long and 1.1” in diameter fits any bottle, cup, or glass.