The unit as a whole works well. My mailbox is only about 80 feet from my home, so I don't know if it works at a distance of 500', but 80' works. The quality of the instructions is abysmal, both in content (especially the APP instructions for the WiFi model) and readability. ABysmal. A sugggestion to the designers: at least make the four SUPER SMALL screws that hold the transmitter base to the body captive, so they won't fall out when changing batteries, or setting the Mode. Dropping one of those screws at the site of the roadside mailbox would probably mean that the screw is lost forever. The unit works as promised, but the "spit and polish" is well tarnished.
Briidea RV Propane Alarm, Propane Gas Detector with 85dB Loud Alarm, 12 VDC $29.99 /WhiteBlackAvailable in 2 colors
