I compared this kit with the appropriate filter BW and Heliopan.
On my Canon 5D MKIII I could not tell the difference.
The thread is a little tight, but returns to normal after repeated screwing and unscrewing.
The filter (SLIM version) are very flat and well processed.
I could not notice any vignetting at 17mm focal length.
Extensive standard accessories as filter box, lens cap and holding bands.
Conclusion:
Highly recommended, very good price with best quality.
