Alphacool Shroud and decoupling 140mm (7mm thickness) inkl. 4x M3x37mm Screws [24831]

In addition, it decouples the fans, which leads to a significant reduction in noise.

Optimization of the airflow
Mounting the fan directly on the radiator creates a dead spot below the fan hub. Even at the corners of the radiator, which are not directly covered by the fan blades, there is little air movement through the cooling fins. By mounting the fan shroud, the distance between fan blades and radiator is increased. This allows an air cushion to build up in this intermediate area. The dead area below the fan shaft is eliminated and the corners of the radiator gets more airflow also. This is especially with silent fans with low speed, the cooling performance can be increased noticeably.

Decoupling and noise reduction
The soft fan shrouds decouple the fans from the radiator frame as far as possible. As a result, hardly any vibrations are transmitted and the noise level is reduced. The greater distance of the fans from the cooling fins also ensures less direct air turbulence at the fan edges and radiator fins. This also contributes to a reduced noise level.