The Water Filter Straw I from Membrane Solutions is a personal water filtration device designed for on-the-go use. It incorporates a multi-stage filtration process, including a coarse filter, PP cotton, granular activated carbon (GAC), and a 0.1-micron ultrafiltration (UF) membrane. This combination aims to remove a wider range of contaminants, including particles, chlorine taste and odor, and a broad spectrum of microorganisms.