I have a large need for such a device but after reading reviews t decided to wait.
1. Only good on Andriod devices -- and only later models of some, not all.
2. Difficult to calibrate and is hard to keep calibrated from reports
3. Look up Walabot reviews from any browser. Amazon has over 30% of one and two star ratings with reasons and comments. but there is a majority of those liking it.
4. Lots of mixed reviews for 2017. Four or five postings and all with mostly less than stellar evaluation,
I didn't provide a link because there are many to read.
This would be so cool if like a Flir(infrared viewer) you could point and shoot in real time to record the activity behind a wall, but they do not seem to be there yet. Even with price reduction I'll wait. They have a great idea but need to do more work.
If you do pull the trigger, write your opinion here after testing.