D40 replacement filter cartridge reduces lindane, atrazine, lead, mercury, greater than 99.95% cryptosporidium and giardia cysts, asbestos, chlorine, sediment, bad taste, and odor. 0.5 micron (nominal) filtration. CBC activated carbon block construction with lead-reduction media. Filter life up to 6 months or 600 gallon. Use with model No. US-600 (SKU 411302), US-550, and CTR-210 filters.