http://www.waterfilters.net/Pentek-DGD-7525-20-Water-Filter.html
The Pentek DGD-7525-20 water filters have two separate gradient density layers that enhance cartridge performance. The Pentek DGD-7525-20 filter cartridge has a 75 micron pre-filter layer and a 25 micron post-filter extra-fine sediment layer. The larger diameter of the pre-filter reduces the particle load to the post filter, allowing it to operate at higher velocities. The effective DGD-7525-20 filter depth is increased to a full 233% of standard spun-polypropylene or string-wound filters. This increased depth provides for very high particulate reduction efficiencies and added loading capacity.
The Pentek DGD-7525-20 water filters reduce the need for multiple housing step-down filtration systems. The Pentek DGD-7525-20 filter cartridge reduces extra-fine dirt, sand, sediment, silt, rust particles, and scale particles. The DGD-7525-20 water filters are manufactured from pure polypropylene and are highly resistant to chemicals and corrosion. The Pentek DGD-7525-20 replacement filters are designed for purity, bacteria resistance, and chemical resistance and will not add taste, odor, or color to the liquid being filtered. The Pentek DGD-7525-20 water filter has three times the dirt-holding capacity of similar sized sediment water filter cartridges. The Pentek DGD-7525-20 water filter is ideal for all residential, rural, commercial, industrial, and municipal applications.