Just recently, I came across this little plastic filter so I initially tried Nico Buster. Now I use the Rsonic filter, I have to say that these are not only much cheaper, but apparently more effective than Nico Buster: The fact that the opening is narrow, the pin toward the opening thicker and also five instead of four holes located in the intermediate piece, a lot more residues in the filter accumulate. I do not think this is an optical illusion.
Conclusion: Good value for money - even if not always exactly the specified 30 filters are included in one package. In this price-performance ratio that is still good to handle.