What makes this Guardline brand stand out is that in addition to brief indicator lightings on house receiver, it has relay contacts inside the receiver. These can output 12 volts DC, or just dry contact closure when a zone trips. I assigned these contacts to zone 1 only, and trigger a wifi relay that sends text messages (with timestamps) to phone texts or e-mail. To multiple recipients too. I wired contacts to a tiny Proteus RC wifi relay for text alerts. I bought the 1/4 mile range model instead of the 500 foot model. Although I'm only trying to receive from 190' away, I wanted it to transmit through couple walls and through steel refrigerator to get to the receiver on kitchen counter. Works flawlessly!! I like how the receiver can display low battery remotely of all sensors 4-AA batteries from inside the house. I only wish the receiver's status/zone light would stay on indefinitely after the chime turns off, and require a press of a reset button. If you're not in the house or room for the few seconds it chimes, you wouldn't know there was an event. Better than most on the market though. UPDATED 3 DAYS LATER:Very happy with the product (1/4 mile GL5000). The primary need was 1 sensor to know when to replenish items in a roadside stand when refridgerator was opened. My wife made many unnecessary 400' round trips each day to only learn it was still full, or hours too late to learn fridge was empty for many hours. I needed a strong transmitter and this unit shines. Also wanted relay contacts to trigger a wall-plug wifi relay (Proteus RC wifi relay) for instant texts when fridge was opened. Works great! HOWEVER, 2nd day when sky was sudden sun, clouds, sun, etc. all day, the sudden heat change triggered many false alarms for a few hours, even though aiming totally away from sun, and shielded in a shaded roadside stand, facing out. I can not tolerate ANY false alarms, as we have the indoor unit up on full volume. One day of that, and the alerts aren't taken seriously. THIS WAS MY MODIFICATION to achieve 100% reliability:I have a single detailed pic with comments on how and where to attach 2 skinny wires onto the circuit board of the outdoor sensor, to trigger from a door alarm magnetic switch double-sided taped to the fridge and it's door. Im counting on being able to attach the pic, as it's "worth a thousand words". While having the 3 screws out to remove the circuit board, I placed a cotton ball and black tape inside the white plastic lens, so heat or motion doesn't trigger the unit. I left the 3-lead infra-red sensor installed and functioning in the event I wanted to easily restore it to it's normal funtioning. There is no need to remove the circuit board if you are willing to simply place vinyl tape on the "outside" of the unit. The 2 skinny wires attached to the circuit board are easily accessed by simply removing the 4-AA battery holder with the 2 tiny phillips screws, seen with batteries removed. The IR element has 3 leads soldered onto the circuit board, and you merely attach to the correct 2 (shown in pic). At the other end of my 14" wire leads, I connect the 2 wires to a "normally closed" switch of any kind (momentary, etc). I used a door alarm switch that has both option screw terminals (common, normally open, and normally closed). I used the common and normally closed terminals. These contacts are held OPEN while the magnet in place with fridge door shut. One of the switch terminals has a 56K ohm resistor inline with one of the terminals in series with one of the 2 wires leading too it. This tiny resistor can be wired in series with one of the 2 wires "Inside" the sensor if you like, doesn't matter. I kept the wires short (14") to insure electrical noise immunity, as the heat sensor detect small signal differences. I tested for false triggers by using a vaccum cleaner and other appliances right near these wires, and NO noise triggered any false alarms. Not sure how long a wire you could get away with, but a long wire could start picking up noise like an antenna. If I can't attach the very detailed single pic of this simple modification here on this updated post, I will try to create a new review and attach it there. This modification eliminates the need for the sensor to aim at anything, or even be in sight. It can be used for a hidden Panic alarm button, or a drawer/cabinet opening alarm. Uses are endless. And NO FALSE ALARMS from environmental spikes, bugs, dew, etc. It has been annoyance free and 100% effective! Now to attempt to attach the pic.......