I tried a couple models before I found this one - Dakota Alert MURS BS-KIT Long Range Driveway Alarm NEW | eBay The Dakota is absolutely fantastic. Comes with multiple configurations - cover just your driveway (ideal if you have a long driveway, stairs, or road that leads up to your house), back yard, alleys, etc. Serves a 'non-survival' purpose since it is great knowing someone is showing up before they are knocking at your door. Verbal announcements for one or multiple zones. For instance, someone coming up the road triggers "alert zone 1" three times. Even has a relay that can set off a 24v bell also. One of the few items that are worth getting. If/when SHTF it will be sure nice to know when someone is approaching or sneaking around your property in the dark. Thought I'd share because just about everything I buy turns out to not stand up to the hype, but these are the real deal. This is all you need if you are covering one approach/driveway -- http://www.ebay.com/itm/Dakota-Aler...349?pt=LH_DefaultDomain_0&hash=item414af4a94d If you have animals running around that would trigger the transmitter and ONLY care about knowing when a vehicle is approaching via a driveway - http://www.ebay.com/itm/Dakota-Aler...668?pt=LH_DefaultDomain_0&hash=item3efa989ba4 Installs parallel to a driveway and senses a vehicle magnetically :0 - cool idea - no need to bury the cable. They have lots of options; call out to walkie talkie, etc.