This round mesh strainer/filter is located inside the fuel tank, at the bottom of the fuel pickup (suction device) on all E10 2002tii models.
This part is listed by BMW as BMW part number 16121106983 (16-12-1-106-983) and is described as Genuine BMW Fuel Filter for E10 2002tii (1971-1975).
BMW Fitments:
2 Series
Vintage 2002 (67-76) > E10 2002tii (1972-1974)