Cokin, whom you may remember - made all those square filters (many for special effect) that came in A, P and later Z sizes. Their latest endeavor is still related to filters - the
Pure Harmonie line. Striving to be the thinnest, lightest filters... Only 3.3mm thick.
It's nice to see such... Thin filters. But I'm not sure exactly why. Sure, to prevent vignetting on wide angle lenses. But the thin filters of today already do that pretty much. To fight bulk? Really? Filters aren't that heavy - even the brass-framed B+W and Heliopan filters (which I use almost exclusively). I'm thinking Cokin is just trying hard to remain relevant.
Okay, so they're not really meant for us I guess. Though I like that variable-ND filter. A shame that like the others on the market, doesn't come in smaller sizes that we can use. They generally bottom out at 52mm. C'mon, somebody make a 46mm!