If anyone has a "TRUGLO RED DOT OPTIC" with flip up lens covers then I have a suggestion for the flip up lens covers. My eye end cover spring got lost because the "retaining rod" backed out and the cap fell off and the spring got lost. TRUGLO doesn't sell just the spring so if you don't want that to happen to you then I suggest that you put a drop of glue on the end of the "retaining rod" to keep it from backing out and losing the spring. The covers are only $10.95 a set but that is a 6pk of beer and it doesn't have to happen!! Just in case you have a "RED DOT OPTIC" that has lens covers. I wish I would have done that with mine but I will with their replacements. Just a note to keep in the back of your mind!!