I've owned six of these security transmitters for about a month now, and am generally pleased with their operation. I own a small 5 acre farm and have them installed all over the property on wooden gates, in a barn, on tractors & equipment, and in a small metal shed. Most of the transmitters cover two separate zones by utilizing both the on-board magnetic reed switch as well as an externally wired reed switch/magnet combination which is connected back to the transmitter via a 3-conductor 18 gauge underground irrigation cable. In this way one transmitter can cover two separate gates and I get twice the coverage for a single transmitter.When I first purchased the units I was worried that range would be a problem as I faced two separate issues: (1) The range from my house to the barn is just over 300 feet which is greater than the (typical) 200 foot range listed in the specifications and (2) the security system receiver is mounted inside a steel frame dwelling which is extensively covered top to bottom in a double layer of 6" thick aluminum-clad foam insulation and all of the windows use aluminum mesh window screens. I was afraid that all that metal would prevent the signal from getting through (I generally have lousy FM and AM radio reception inside and need to use external radio antennas) but it turns out that the receiver has caught each and every signal that the transmitters have made - with just one notable exception. The transmitters DON'T like to be mounted inside metal outbuildings, such as an aluminum or steel shed. Enough RF cannot get out of the shed to make it to the receiver 200 feet away in the metal house. In fairness to Honeywell, however, this issue is mentioned in their brochures, and I solved the problem by simply re-mounting the transmitter outside (guarding a gate next to the metal shed) while I ran underground irrigation wiring into the shed to catch a sensor inside. Works great this way.Thus far, the sensors have shown great reliability and better than advertised range, assuming that you keep in mind some simple common-sense rules with respect to mounting (don't bury them, encase them in metal or metallized paint, look for line-of-sight propagation paths, and keep them as high as reasonably possible above ground). Programming went without a hitch and they interfaced perfectly to a Honeywell Vista-50P security system.The only down-side to the product is that they are much larger and bulkier than the usual Honeywell RF sensor (making them more difficult to hide - but they are designed to be painted in order to help camoflauge them) and they are pricey, which I guess is what you pay for Mil-Spec performance. Overall, I'd recommend this product if you are looking for all-weather performance, good range, long life, and high reliability. Be prepared, however, to lighten your wallet a bit in order to gain these advantages.