CPVAN Indoor Motion Sensor Alarm with Siren, Remote Control Wireless Infrared DIY PIR Motion Detector Burglar Alarm System, 125dB Adjustable, Battery Operated, for Home/Shed/Garage/Van/Shop.

Bought 2 for my garage - they work as indicated. I have one pointed at my side door and the other at the main bay door, both paired to one remote. Nice and small, easy to install wherever you need them. Alarms are loud and remotes work well (and at a distance). Best things about these: - Remotes are interchangeable with each alarm - You can program multiple alarms to one remote (and multiple remotes to alarm groups). So buying 2 alarms means you can have a spare remote - Alarms can be powered via micro USB (but you must buy your own USB cables to power them). Very handy to avoid battery replacement! If you can, get an "elbow-jointed" micro USB cable as the cord can get in the way of the mount. That said, I positioned mine as needed without issues.

Sometimes, the Motion Sensor Alarm would not arm itself. At other times, the Motion Sensor Alarm would go off even when it wasn't armed.

This is a must have for me. I may buy more. It's loud enough to detour my Beagle from eating everything in sight when I remember to turn it on. I have cats that fight when they get close. They pretty much ignore it but it alerts me when they get near each other's territory. Animal people have so many uses for this alarm

Dont expect Fantastic BUT as a deterrent and a "bit" of peace of mind go for it. Pretty loud and maybe enough to put the opportunist of and leg it or at least alert you. To be fair a Good bit of kit for the cost. I have on on my garage and now this in my van.

Works very well, good and loud. I use rechargeables and they last months despite me tripping it frequently. Effective deterrents if the mains fails.