Williams Twilight Aperture
Twilight apertures are designed for shooting under
poor light conditions, early morning, late evening,
and other inclement conditions. They create a sharp
contrast that gives quick definition to the aperture
hole, and they eliminate the “fuzz” with which many
shooters have trouble.
These apertures are perhaps the greatest development
in metallic sights in the last three decades – positive
sighting when the light is poor but the hunting best.
For FP-AG and FP-GR aperture sights.
3/8” O.D. with .125 inner hole