I purchased a sightmark reflex sight in January of this year. http://www.sightmark.com/products/reflex-sights/ultra-shot-qd-digital-switch-sm14000
The sight started shutting off on me during a course of fire. I contacted sightmark about this issue and was pretty much told to go get screwed since I did not keep my proof of purchase. These products are junk and their customer service is the worst I have seen. DO NOT WASTE YOUR MONEY with this importer of cheap garbage.