The robust pre-filter can be optionally attached to the submersible pump. The use of the pre-filter is particularly recommended when operating the pump in heavily contaminated water, such as in construction pits or during flooding. The filter can retain large dirt particles from entering the pump. This protects the pump impeller and prevents clogging of the pump by branches or dirt particles, thereby increasing its operational reliability. The pump pre-filter is suitable for submersible pumps SP 1 to SP 5 Flat/Dirt and has a mesh size of approximately 5 millimeters.