You have to know they aren't really ND but something between dark bluish-cyanish. Both the regular ND and hard gradient filters are colored. What that means? If you shoot sun rise/set using a gradient it will produce colder sky colors, its possible to warm the sky using 'shade' or 'custom' white balance but the foreground on clear part of the filter will become unnatural warm which will be seen easily. Same thing is if you shoot during the day but the effect will be less visible. Well maybe in autumn it will be OK it will warm background but what about other seasons? Anyway if I want so much to warm the background I could use yellow or orange gradient (clear part up) but I have a choice, using Kood I haven't such. It's OK if you use the regular ND - it will make colder all the scene so you could fix the 'color shift'. These filters are cheaper than Cokin ones but Cokin is real ND (i have NDx4 grad Z-Pro). The bad thing is Cokin does not have hard grads. So keep this in mind if you are to buy Koods. Also take a look at these photos - real one is by Photo Accessories Wales! That's how Kood filters look like. The other photo only shows how the real ND shoul look like.