The Omnipure (E5521) is a 10 Micron GAC filter cartridge. This filter also features a universal cap that fits all permanent existing heads which makes this filter easy to install and remove. This filter also aids in the removal of taste, odor and chlor Additional Details ------------------------------ Product description: The Omnipure (E5521) is a 10 Micron GAC filter cartridge. This filter also features a universal cap that fits all permanent existing heads which makes this filter easy to install and remove. This filter also aids in the removal of taste, odor and chlor