Measure your device’s actual power draw (check router + ONU power consumption) so you can estimate how long this UPS will last.

Ensure the connectors match (voltage, plug size, polarity).

Place the UPS in a cool, ventilated area—not in a sealed cupboard with no airflow.

For best battery life, avoid deep discharging it completely every time; recharge after moderate use.

Consider a surge protector or check that the UPS has built‐in surge protection if you’re in an area prone to voltage spikes (some listings mention “protects from thunder surge voltage”). smartzen.com.bd

Keep the firmware / device environment of your router clean (fewer processes/higher load means higher draw).

If you buy locally, ask for serial number / warranty card and keep the receipt in case you need service.