The manufacturer informs:  

Sistema di raffreddamento a 4 elementi per acquari aperti.
They help to lower the temperature by up to 4°C lower than in the tank (depending on the ambient temperature of the room where the aquarium is placed).

Ideal for customers who have no special refrigeration needs and do not want to make a major investment by purchasing an electronic chiller.

Technical specifications:

• voltage: DC12V
  
• power supply: 220-240V 50Hz
  
• consumo: 3,8w
  
• rotational speed: 2800 +/- 100 RPM
  
• noise: less than 40dB
  
• dimensions: mm290x152x65
• for glass up to 20 mm thick