Fillers and / or growth body of plastic

Fillers and / or fouling body made of plastic with an outer casing (1) of polygonal or cylindrical hollow profile of a certain length, having provided on the periphery of through holes and / or interruptions and at least one inner concentric inner casing (5) of polygonal or cylindrical hollow profile, with the outer shell (1) is connected stably interposed webs or fins, wherein the outer shell (1) cylindrical shape or a polygonal cross-sectional shape and at least one helix (2), which extends in such a way that between the adjacent helical threads, an opening gap of constant width is given, characterized in that the inner casing (5) is composed of at least one helix (5).