I bought this for a G2 LED. When transitioning from normal LED to the red filter, there seems to be significantly less light throw, although it seems to get better after my pupils have acclimated to darkness. It's still not quite as good as I've gotten from red filters over incandescent lights. Also, there seems to be white light escaping from the edges of the filter close to the lens. It doesn't travel very far, but I would have expected it to give off zero white light.
Pros: Flip up cover keeps lens from getting scratched
Cons: Severely diminishes illumination
This review was written in the old system and had content requirements that are different than reviews written today.