These recurve sight pins glow in the light. Instead of just a glowing dot in a dark circle, the circle glows, giving better definition of the circle in relation to the target. It is a unique view of the target and can be especially effective in dimmer light.
Since it is a ring, it helps aiming, and keeps you from over aiming or tensing just to keep that little dot steady.
Depending on the distance the sight extension is set, the glow can be made to look like it sits in one of the color rings of the World Archery target.
Which color works best depends on the color of the target and how you see.
8/32 thread in four colors: yellow, orange, red, and purple