A drain filter holder.

Fits a drain pipe with a diameter of 132mm. A base that sticks into the drain pipe, and one that fits into the base with a filter in between. Use a regular mosquito net or similar fine-mesh net. The straight edge of the base, and thus the necessity of support, is by design. I wanted it lying flat against the drain pipe, not chamfered (which would have meant that support was not needed) so it lies well without being wedged. Intended for 50mm pipe from washing machine or similar. Easy to scale to fit other diameters.