The second generation UniFi switches bring many changes and improvements, the switches have been redesigned from the ground up. Compared to the first generation, there is a significant improvement in airflow , which is used for cooling, making it up to 4x quieter* than the first generation. * at an ambient temperature of 25° and a 25% POE load, the switch is 3.6 times quieter * at an ambient temperature of 25° and a 50% POE load, the switch is 4.2 times quieter * at an ambient temperature of 25° and a 100% POE load, the switch is 1.9 times quieter Equipment USW-Pro-48-POE Gen2 has a total of 2