We have added something special to our Aquavein packaging at no extra charge! The R&D Aquaveins' patented and proven design hasn't changed. However, for those who ride in the ocean or very rough conditions we have added shims to the kit. The shims allow you to lower the wing which will load your GPR pump with more water adding extra pump efficiency and traction! In rough water conditions average speed increases with the added hook up. The shims create 3 selections to choose from, R&D's "easy install" directions show you how in minutes!