Tragic construction. To change batteries, you have to solve the whole ups, their fan makes annoying noise, and the wiring configuration is dangerous. You don't even see such construction in cheap Chinese products.

I have had it for 3 years and its batteries are still in excellent condition. It provides enough power (15 minutes) in a system that is approximately 300 watts idle (monitor, computer, amplifier, lighting).
So, I will mention 1-2 negatives that do not, however, hinder safety during a power outage.
1. The fan makes noise while charging (several hours when it is empty).
2. The software it has, while updating correctly, does not save the settings you give it (at some point it works afterwards, but it's like it doesn't save anything).
The positives, apart from its quality and reliability, are that it does not have any coil whine like another one I have from a different company.
Also, when winter comes and the temperature drops significantly, the UPS starts and performs small charges to better maintain the battery (I have confirmed this after a phone call to their headquarters where they were very helpful).
Overall, I would buy it again and in the future, I will definitely get one for the TV, not of course a 1500W one.

19/12/2021

I changed the batteries after 4+ years and it continues to work like the first day. The operating system, since I switched to Windows 10, keeps the settings, so the second negative point I mentioned above was related to Windows 7 (at least for me). I would definitely buy it again.