Review on Stay Safe And Secure: Wireless Motion Sensor And Pager Bed Alarm For Elderly And Kids by Patrick Cooney

2 receivers=sound on all levels. Although I am not quite sure I need more than one receiver. For being so small, this thing is LOUD. Thankfully, the volume has 5 levels, because I about jumped out of my seat the first time it rang. I plugged my receiver into my internet router (charging block is not included) because its hidden and it saved me from plugging a charging block in for the included USB cable.The portion that goes outside can be attached with pre-cut 3M adhesive or with 2 (included) screws. The holes are not pre-drilled but have clear places where they should be drilled. I used the adhesive and the screws so there would be zero chance of this coming loose. I live in the northeast so cold weather and snow are something I deal with ever year. I cleaned the siding with alcohol first, then attached with the adhesive strip and screws. So far, even with weather in the teens, this has worked as it should.