Pentek WP5BB20P String Wound PolyPropylene Filter-4.5 x 20/5 Micron MERV 11 Air Filters They are specially treated with

They are specially treated with an anti-microbial barrier which also increases the efficiency of any humidifier using the Bemis 1041

Reduces hardness that can cause scale build-up

15x25x1 MERV 11 filters are right on the cusp of being classified as “medium efficiency MERV pleated air filters” and “high-efficiency MERV pleated air filters

Aprilaire 500A Humidifier

Pentek WP5BB20P String Wound PolyPropylene Filter-4.5 x 20/5 Micron MERV 11 Air Filters They are specially treated withThe Pentek WP5BB20P String Wound PolyPropylene Filter improves the flavor and reduces the metallic taste caused by iron. It combines quality and functionality with durability for a lifetime of customer satisfaction. It is convenient and cost effective for many applications. Specifications: Micron Rating 5 Flow Rate up to 40 GPM Cartridge Dimensions: 20" Long x 4 1 2" Diameter reduces sand, dirt, silt, scale, rust, and sediment particles The WP5BB20P