Purchased 9 years ago. My daughter used it until she was about 2 years old, and after not using it for 5 years, my son, who was born after her, used it for about 2 years. Our house is a detached house, and we can transmit video and audio without any problems from the bedroom on the second floor to the living room on the first floor. I just checked the operation and it worked without any problems. The third photo shows the state with the light on, and the fourth photo shows the state with the light off. However, the battery is weak, so please be aware that the monitor will run out of charge quickly if the adapter is not plugged in. I was supposed to have kept the instruction manual and the box, but I can't find them... The initial settings have been completed, so basically, you can use it immediately after turning it on. If anyone is interested, please let me know.