The alarm is very sensitive. Mine starts beeping without any movement. The mobile application is not being updated. It was updated at some point, but not anymore. It has bugs and is not available on the Play Store. I asked Geyer Hellas and they sent it to me via email. In the end, I replaced it and installed a Chuango alarm and I am much more satisfied.

It does its job but its functions are limited.

Positives:
Very easy programming from the application.
Very fast notification and call (approximately within 10 seconds).
Does not go off without reason like other alarms.
Does not disconnect from Wi-Fi.
Affordable and attractive peripherals.
All peripherals have tamper protection (if moved or broken, the alarm will go off even if it is unarmed).
The central unit has an internal battery in case of power outage.
The strobe siren has an internal battery in case of power outage.
Good technical support from Geyer.

Negatives:
Does not have Wi-Fi disconnection notification.
Does not notify you during arming if you have forgotten a door or window open and arms even if everything is open.
Neither the unit nor the application notifies you if any of the peripherals' batteries run out.
The strobe siren only flashes when triggered, it is off the rest of the time.
Needs to be placed inside a box (not included) to be hidden because it has an on/off button, which if someone enters the house and hits it, they can easily deactivate it.
If the router malfunctions, it goes off but does not send a notification or make a phone call, so it should also be protected and have a UPS.
Overall, the manual is incomplete and does not adequately describe the functions, resulting in functions that I do not know what they do.
The equipment is from the Chinese company Kerui with minor modifications in the application by Geyer and menus in Greek, but if you buy it directly from Kerui, I don't think you will practically find a solution in case of a malfunction with the warranty, and I also believe that technical support will be nonexistent, which is why I chose Geyer.

Conclusion: It is reliable and does its job, but I would not buy it again. I would prefer the more expensive model that costs about €110 more.

The best in its category with a multitude of functions, mobile app monitoring in Greek, and generally much more than I expected!