ORIGINAL: amayerican
There’s a lip added for a more twist. Just like a plane; the little flap on the fletching hit by the wind makes the arrow spin more. More spin = more balance = flater shooting
That's a NAP QuickSpin you're thinking of.
I can't say much for the Blazer vanes since I haven't picked up a package yet. I plan on shooting them this summer. They're supposed to increase consistency with broadhead flight. I haven't heard any negative feedback on them though.