Centrifugal trash pumps pass foreign material such as stones, leaves, mud and various other solids that can clog other pumps. Should clogging occur, you can easily remove the clean-out cover by loosening the hand knobs; no tools required. Trash pumps pass solids half the size of the suction opening, i.e., a 2" trash pump passes 1" spherical solids. Our pumps also pass up to 25%, by volume, of sand, silt and mud. Units are self-priming, and once you fill the casing with water, you're ready to go. The heavy-duty tubular steel frame increases portability and component protection.