This is a holder for a Gentech VCS-02 float switch. It affixes to a vertical surface (perhaps by screws, or by cable ties etc), and provides a bracket from which the float switch can dangle.

Pretty standard printing specs for this part - it's not especially complex to print. You may find setting a "minimum head speed" may be beneficial in some areas of this print.

Once printed, the float switch should fit easily in the hole provided. To fix the bracket to a veritcal surface, either drill holes and use screws, or affix to a pole, stick or other with cable ties (which happens to be my favourite solution).