Over time, natural wear of the impeller may reduce pump performance. Replace the impeller to ensure reliable performance. Replacement Impellers are available for Mag Drive Pump Models 500, 700, 950, 1200, 1800, 2400, & 3600. Pump Cover Replacement pump cover (volute) for Mag Drive Pump Models 500, 700, 950, 1200, 1800, 2400, & 3600. Includes Pump Cover and O-Ring. Pre-Filter The pre-filter helps prevent premature pump damage by keeping debris from entering your pump. For optimum pump protection, replace old or worn pre-filters. Replacement Pre-Filter Sponges (cylindrical style) are available for Mag Drive Pump Models 500 and 700. Large replacement Pre-Filter Sponges (block style) are available for Mag Drive Pump Models 950, 1200, & 1800. Plastic Replacement Pre-Filter (rigid, finned style) are available for Mag Drive Pump Models 950, 1200, 1800, 2400 & 3600.