And carry spare at all times...Out today cutting firewood and one thing lead to another and wood cutting usually turns into some sort of marksmanship challenge among friends. We spotted a rim in the brush so I grabbed my shotgun trying to beat three others to the “punch”. Flipped off the hood to my sight and no dot…..Now I have grown up with a gun in my hand and fancy myself a good shot. I have always thought that if my dot goes out I could still probably get lead on target….well that was a bunch of BS….I couldn’t hit the ground. I tried at first a couple quick ones trying to hit the rim that was 25 yards at most and missed low by a ways. Then I really took my time and tried and still couldn’t hit the rim with buck or slugs…..I was very surprised and disappointed. The good news is that I carry the tool and spare batteries on the gun at all times. I removed it from the base and replaced the battery in less than a minute and put a serious hurt on that rim… but still in a scuffle that’s enough to die trying…..I do have the bead for back up but would have to remove the reflex all together to use it….which is doable with the tool I carry.