I purchased a package of 3 filters that were intended for the Phantom 3, they do indeed fit my Phantom 4. This video is just showing proof that the Phantom 3 filters will indeed fit the Phantom 4 camera. I was worried about them not fitting on the Phantom 4, even though I read several articles stating that they would fit on my Phantom 4.
The filters are from Polar Pro who make all sorts of accessories for drones and GoPro cameras. The three-pack I purchased included 2 ND filters; a ND4 which is a 2-stop filter, and a ND8 which is a 3-stop filter. Also included was a circular polarizer filter as well. Included with the filters were 2 carrying pouches. The filter set retails for $49.99, you can get them from Amazon: http://amzn.to/1YSMquI.
I have not yet had a chance to shoot with these filters to give any sort of opinion on them other than they do indeed fit on a Phantom 4. I will do a separate post and video on the filters after I have tested them, as well as do a comparison video with the filters on versus the filters off.
If you have any questions, feel free to reach out to me on Twitter; http://twitter.com/icrizzo.