I just received the all day kit but I am thinking of returing them.  On each of the polarized filters, the polarizer does not turn very smooth.  They feel gritty as if there are metal fragments left behind from manufacturing. Each filter feels a little different and some feel like the polarizer portion is loose.  Anyone else notice this?

I just got the All Day 8 pack yesterday for the OA. The rings on the polarizer ND filters and CPL seem smooth to me. They all don't have the exact same pressure to turn but they all feel smooth.
I'm happy with the build quality, the turning rings feel solid.

I also have their Budget 6 pack filters for the OA. There are 2 ND/PL filters and a CPL filter in this pack. The rings on these feels a little rougher spinning but the build quality seems good. The filters in this pack have uncoated glass.

I would think / like if the CPL part had some resistance to it when turning it, but of course not so much you would risk unscrewing the entire filter from the OA if you had not tightened it really hard.

But the grittyness you mention sound like something that should not be there, so i would for sure reach out to freewell and see what they have to say on the matter.

Thanks.  I am going to return them.  I know they have lifetime warranty but I am not confident that based on how they feel new that they won't fail at an inopportune time.

Hello and good day col4bin. Thank you for reaching out and for sharing these information with regards to the ND Filter you have purchased for your DJI Osmo Action. Just a friendly reminder that we do not recommend you to use a 3rd party accessories or devices on your DJI Osmo Action. Actually, there is a  possibility that this accessory will work, however, since it's not yet tested by DJI we cannot guaranteed the reliability of the said accessory when in use. In addition using 3rd party accessories or devices might cause damage or harm on the DJI Osmo Action and can void the warranty as well. Thank you for your understanding and valued support.

Nobody tried the Polarpro filters ? It's what I ordered. I use the polarpro on my mavic air. I never tried freewell but I'm happy of my polarpro ...