Today I replaced the follower in my Mossberg 500A 12 Gauge shotgun with a Go Gauge LED follower. It is a white follower that has an impact-sensitive LED inside that lights up when you fire. When your magazine runs dry, the light is visible in your chamber, making it clear that it’s time to reload.
The light looks strong, but it does not project, so it does not light up everything around you, even in the dark. But now even a quick glance at the chamber cavity will make it clear if you’re loaded or empty. Neat idea!