I have used my original [Nite] Guards for 3-4 years now without any problems. I have them around my chicken coop. I have not lost any chickens to any pred[a]tors. My neighbors across the street ha[ve] lost several of [their] chickens to coyotes or bob cats.
I highly recommend this product to anyone.
Do not waste your money on the cheaper brand called Nite Eye. I thought I was getting Nite Guard from Amazon and did not. They were not worth a hoot. We have extended our pen and will be ordering more. You will not be disappointed.
Try one out for yourself. It is more than worth the $19.99.