High elastic silicone frame gives a good protect to the glass, making the filter fit many flashlight models in almost any environment. Red filter- Used for emergencies, caution, traffic signal and Hunting to not spook game. Great for penetrating fog or smoke. Does not disrupt night vision. Green filter-Used for hunting and hiking. Green is also very popular for night time map reading and covert operations because it does not disrupt night vision. Blue filter- Used for night fishing, tracking wounded game, and close reading. FT12:Can be compatible with around 45mm bezel(like XT12GT/XT15).