Window Alarm System 4-Pack - Ultra-Loud 120dB Alarms with Advanced Vibration Sensors - Window Security Alarms for Glass Break Detection - Features Low Battery LED Indicator

One of the teeth is broken

They do work especially if I open the patio door and forget to turn it off! The flashing light is hopefully a deterrent and the sticker on the back that goes against st the wi down another warning. Highly recommended

Excellent. The batteries so far with it blinking 24/7 has lasted 4mths. I live the warning light and decal as would be thieves will be able to see you have glass break vibration from the outside so a great deterrent. When installing the batteries the alarm will sound and it is ver loud. I have a dog and it was so loud and high pitched that I had to go into another room and close the door to put in the batteries as it even hurt my ears. Just turn it off immediately after inserting batteries but you do want each to go off initially ti ensure it works.

Works great

Muy bueno la alarma se escucha bastante fuerte, solo aveces he probado y no se activa, no se si necesite mas sensibilidad

Super easy to install, but because they are so large you need to think about where you're putting them. Make sure you can slide off the battery case when it comes time to replace the batteries. One of mine I stuck too close to the wall next to the window (live and learn!) and will probably have to peel it off when it comes that time because I didn't think it through until AFTER I stuck it on. The adhesive is very strong! They are large, so if you want to put them on the stationary part of the window, make sure you leave enough room to open the window. I love the flashing red light, which is easily visible from outside, and lets people know that there is an alarm. I like to think this is a deterrent in and of itself. Even if it's not, the alarm seems to be adequately sensitive. I have one on a living room window and was having new flooring installed. The installer dropped a tool near the window (it was a pretty loud bang when it hit the floor) and that set the alarm off. I was very relieved to know that it worked. Let me tell you, the alarm is LOUD! I heard it over the power tools the intallers were using--it got everyone's attention. I mentioned the flashing red light--think about how that might be seen from inside your house before you install these, too. One of my alarms is in my living room and I had to place it so it won't be seen at night from inside. That would be super annoyng. I can see where it could be an issue in a bedroom if there's no curtain or other window covering that could block out the light. Overall, I am super happy with my purchase and I feel more confident that those vulnerable windows are less vulnerable now. I like that these use AA batteries, because I always have a number of them on hand, but that is what makes the alarms so large. So, bottom line, make sure the size of these alarms works for you and that the flashing red light won't bother you. I would recommend this product.