The best filters out so far for the Inspire were custom-designed by a forum member - Renaat - and outsourced to a factory which produced them to spec. The thread where the first production units were evaluated is here:
PeteGould Posted at 2015-5-15 05:19
The best filters out so far for the Inspire were custom-designed by a forum member - Renaat - and ou ...
I'll confirm with Pete. I just got my set of ND filters and have only had a chance to fly once with the #ND8 and I'm very happy. I purchased two complete sets, ND8,16,32,64.