Just picture your arrow going down a shaft not much bigger than itself between the string and riser at full draw. as it is released it goes perfectly through that shaft without touching the sides. That's center shot. A Whisker biscuit is like that shaft an actually helps you achieve center shot. There's a price though and a better way to shot through the center of the bow. But if you can't tune your bow ,they help, and is a reason for their popularity.