Rheostat Fiber Rings allows the user to adjust Glow Pin brightness for individual target presentations. Rheostat Fiber Rings can also be used without a Glow Pin – use a drilled lens and fiber, eliminates the distraction of seeing the Glow Pin! Turn the cover to expose more fiber to increase pin brightness, cover up more fiber to reduce pin brightness! Rheostat Fiber Ring comes with green fiber installed, but also includes red and blue fiber. Available in .010”, .020” and .030”.