What are the best for sand dunes?

Are Geckos any good?

 

I just bought Maxxis Sur Tracks which can be used in sand, snow and mud. They are reversable. I ride in all three. I hear they do awesome in sand, but I'll find out this weekend when I test them out at the sand dunes when I go camping at SILVER LAKE! Can't wait. I got holeshots for the front. Good luck!