I dunno. I have two properties and I have them mounted all over my houses (especially areas that are not well seen from the street, etc.). Mine have lasted for YEARs and yes, most of them are the cheaper, plastic, box store units. From what I understand, they detect movement passing by in their detectable field range meaning that someone..or something would have to pass across it. Simply standing and waving your arms in front of it doesn't make it trip on. I usually have to fiddle with the placement of the sensor, sensitivity of the sensor, etc. to get it to my liking. My only problem is with critters...or windy days....I will get false trips.