I changed the battery on my X5L Gen2 and it did not turn back on. I thought it was the battery I was using (a trustfire cr123 from
dx.com) but it was not. I sent am email to Viridian customer service and received a response from them in about a day. Had the light, in its original box (I do not through out original boxes) out UPS to them, per their recommendation. Less than a week later I have the same serial numbered unit, with a new laser and a sticky on the box, "bad laser, replaced
+ checked." Now it works. Still have to get it to the range and re-zero it, but a big plus one to Viridian for awesomely fast customer service.