Based on this product's specifications, here are some alternatives and similar models
Sera suction pump for Fil 250 / Fil 250+UV / Fil 400+UV, replacement pump SE-30643
Summary description:
Replacement suction pump compatible with sera Fil 250, Fil 250 + UV and Fil 400 + UV filter units (model SE-30643). Designed to restore water flow and filtration performance in external aquarium filters, it fits original mounting points and connects to existing tubing and power assembly. Ideal for repairing or maintaining filtration systems to ensure continuous water circulation and mechanical/biological filtration.