This shroud improves the cooing performance of your fan/radiator combination. Mounted between fan and radiator this shroud allows more even distribution of Airflow which allows a more efficient utilization of the radiator's fin surface. If mounted directly onto radiator a deadspot between the fan motor is developed which reduces the performance. Even multiple of the shrouds can be stacked with longer screws to further increase efficiency and performance. The used material ensures a better seal between fan and radiator which also helps to direct all of the Airflow through the cooling fins.
The material, hard rubber with a thickness of7mm, decouples the fan from the radiator. This mounting method is a must especially with fast fans as the emitted vibrations might otherwise cause the whole case to vibrate noisily.
Can be used in multiples over double, and larger rads!