Atlas A 20 inch mechanical filter is a large-sized filter housing used for the initial stage of water purification. This system is usually installed in home, facility and industrial water lines and effectively retains sand, rust, mud and other large mechanical impurities in the water.

The 20 inch size means the filter has a larger volume, which means it can hold more water and last longer. It usually contains cotton (sediment) or other filter cartridges.