The product links are on the main article at GunsAmerica Digest. There are two sides to the subject of perimeter alarms. On the one hand, it is a life saving precaution to warn you if someone is coming,

Did you already buy a ton of freeze dried survival food? Well there's no harm in that, but if you really take a look at what you get vs. what you pay, most likely you only got about 100-300 calories for