I thought I would advise any prospective buyer of Eotec to consider my recent experience with their customer service. I have an Eotec 512 that I purchased about six yearsago. It recently failed to power up. i replaced the batteries and contacts. It will still not power up. I contacted Eotec and they said that because of the age of the sight they could not repair it and suggested I use their trade in service. I can honestly say the sight was never on more than an hour all the time I owned it. It was never misused as it sits on my AR15 behind my bedroom door. I think I am going to buy a Lucid sight at much less cost and with excellent reviews.