The AO Smith AO-US-RO-MEM Membrane Stage 2 Replacement Water Filter is a black plastic filter designed for the Aqua Optima Evolve model. It is a 2-stage reverse osmosis filter that can remove contaminants such as asbestos, chlorine, pesticides, lead, and mercury. This replacement filter is suitable for household use and is an essential component for maintaining clean and safe drinking water in your kitchen. Made by A. O. Smith, this filter is a reliable and efficient solution for purifying your water supply.