Dual Gradient Density Filters work as a pre and post filter all in one, eliminating the need for step-down filtration systems in your home. The outer layer is a 150 micron pre-filter that takes out larger sediment, thus reducing the load on the 50 micron inner-layer post filter allowing it to operate more efficiently and consistently.
The pure polypropylene construction makes it resistant to chemicals and corrosion. 
Features:

• Will not add taste, odor, or color to the liquid being filtered
  
• Designed for purity, bacteria resistance, and chemical resistance
  
• Reduces extra-fine dirt, sand, sediment, silt, rust particles, and scale particles
  
• Has three times the dirt-holding capacity of similar sized sediment water filter cartridges
  
• Ideal for all residential, rural, commercial, industrial, and municipal applications
  

Fits American Plumber, Aqua-Pure, Culligan, Pentek, Ametek and other 20" Big Blue Housings.