The Pondmaster 02710 Mag-Drive Pump is a magnetically driven centrifugal water pump. It has no seals to wear and contains no oil. This pump can be used submerged or inline and all electrical components are encapsulated in epoxy. The energy used is approximately 1/2 of regular driven pumps, and the pre-filter is provided for use in situations where debris in the water could clog or damage the pump, helping to give you uninterrupted service. In order to start your Pondmaster 02710 Mag-Drive Pump, the pump must be below water level and filled with water. Unless the air can escape from the outlet, the pump will not start. These pumps have been fulfilling the needs of professionals and hobbyists for over 10 years with efficient, quiet, and reliable 24/7 performance.