ok done some research onthis first off i was told that a coyote had vision comparible to humans with that said you should be able to make your judgement but..... varmints that are color blind (which is most of them) can only see the green and blue parts of the uv spectrum which means that they can see blue and green colors/lights. therefor if you are only hunting coyotes you could use the green light but other varmints that might respond to the calls could be able to see the light. i dont think that the lense covers made to make the light invisible to the varmints just to filter it enough so the varmints can look with it not hurting there eyes in turn letting us see the eye relection. so with that said it is your personal choice on whichone you use. i personaly do a lot of calling and have used all of the filters. i have found out that the red is the best followed by the amber. the varmints (i mainly call cats, coons, fox,and yotes here in tx.) will look at the light and people can see good enough to shoot well.
just my 2 cents hope it helps
green light vs. red
