You can get them for about $20 and they look very realistic. You need 2 AA batteries for the red LED to flash. Since 1 LED draws almost no power I think the batteries should last a while. I simply glued them to the wall with quick drying outdoor construction glue. this works great and is a lot quicker than trying to screw it into a plastered wall. I just need to trim off the excess glue when I have time. I am very happy with it.
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