The Extra Large Filters are two-piece bayonet-style replaceable cartridges that work with a permanent head. The Omnipure is a 5 micron granular activated carbon filter that reduces chlorine taste and odor. and more! The Omnipure ELF cartridges offer the best cost-to-performance ratio in the industry! The Elf series filters are perfect for commercial applications and the food service industry.The Filter has a scale inhibitor for equipment protection. The Omnipure has KDF which is specifically designed for reducing water-soluble heavy metals. and controlling scale. bacteria. and algae. The Filters are perfect for use with water coolers. commercial and residential drinking water systems. and pre and post RO filtration.