I bought this unit because it said indoors/outdoors. I wanted one for outdoors. I also read the other reviews.....including the reviews saying easy to add to your system.........well my system is the skylink SC1000. so this motion sensor is not compatible with it. I would like skylink and amazon to advertise that this sensor is only compatible with the 318R receiver. Please do so with all the accessories. By the way my sc1000 works well. good system.