aquarium heater with

Condition: used, no box,
Function: It is designed to heat water and maintain a set temperature, commonly used in fish tanks.
Controller: The white box is a temperature controller that plugs into an outlet, allowing you to set and monitor the desired temperature.
Sensor: A probe from the controller likely measures the water temperature to adjust the heater accordingly.
Safety: Ensure the heater is fully submerged according to the manufacturer's instructions before plugging it in to avoid damage or failure.