This is not your standard $50.00 shop vac. The primary filter is 100% woven polypropylene. Ideal for heavy debris applications where you will be required to continuously clean the filter element. The Polypropylene filter element is sturdier than standard Remay material and ensures many washes, rewashes, use and abuse. The secondary filter will grab the remaining debris down to 20 micron ensuring the remaining waste is filtered simultaneously polishing the water before being returned via the discharge port.