The package finally arrived, it's not lens caps this time. :-)
They come with a nice plastic case, those transparent cases which screwed together by friction, pretty standard for filters like this.
To my surprise, the filters are with different colors! Despite they all marked with (25), but they're totally different!
One of the 52mm is darkest among three, and another 52mm is slightly lighter, and the 77mm is brightest! Seems like that I've to email them to ask why.
The two 52mm when stacked together, is good enough to serve as ERF, since there will be a layer of air between and the transmission is low enough. The 77mm one, however, is probably too light color, even lighter than the 6.5" aerial filter (to be used with a C5, cell pending).
The top line from left to right are: Polarizer, ND3 which are used with the Herschel Wedge, next is a UV-IR block from Baader, and the last one is a CaK also from Baader, to be used behind the Herschel Wedge, too.
The three red colors are what I described above, they're supposed to be the same color, but they're vastly different. They're used as ERF, I called them Cheapy-ERF in general. The dark one on the far right is a IR pass filter.