Bests & Worsts Reviews from Amazon

I originally liked this idea of doing my own home security. I put up 13 of these sensors across my home. Some were on windows and some were on doors. Within two weeks of them being in use, 5 sensors failed. They all initially said low battery but then when I switched the battery with a new one they wouldn’t turn back on. Amazon sent me 6 new ones for free and out of the 6 new ones they sent me, 3 said low battery out of the box. I’m not sure what’s really going on here but i spent a small fortune on these sensors for them to be failing within days of coming out of the box. Very disappointed.