In this video, Lancaster Archery TechXPert Dan Schuller describes how the Range-O-Matic Spin-Wing Vanes work. He talks about how they should be attached to an arrow, and how they will benefit target archers.

Because of their curved shape, the Spin-Wing vanes cause an arrow to spin more than normal fletchings. That spinning motion helps stabilize the arrow in flight. The vanes come in a variety of lengths, so you have several options to choose from when fletching your arrows.