I have this system and it works fine. I placed the transmitter on my front porch so I get an alarm when someone approaching the front door.
Both the transmitter and receiver operate on batteries. The transmitter runs on AA batteries and they last for about 6 months. The receiver uses C batteries. But, you can buy a AC power module so batteries aren’t required. I plug the power module into a wifi enabled plug. I schedule the wifi plug to come on during hours of darkness. So, the alarm will only sound when it is dark.
The alarm has different sound settings. One is a loud alarm sound, the other a “ding dong” doorbell type sound.
I love mine! My driveway is long so I put both sensors alongside about 40’ apart. That way when I hear both of them alert, I’m pretty sure a person or car has triggered it. My receiver picks up signals very well at 100’ away in my living room.