I have one of these puppies for my surefire 6P weaponlight, and let me tell you, they are well worth the money. The purpose for the filter? When operating in low-light conditions, they allow the operator to keep their adjusted night sight (their night vision, vs being blinded from the white beam). The beam, when colored in a different tone by these filters, makes the beam itself virtually invisible. When clearing a target building at night, opposing forces cant't as easily see your team in the building you are clearing when using these bad boys. For survival, their stealth applications, and their overall cool look they are well worth the money!
none 
