Different bearing types have unique pros and cons. Ball bearings excel at durability and can last up to twice as long as sleeve bearing designs. Two tried-and-true Axial-tech fans feature a smaller hub that facilitates longer blades and a slimmed down barrier ring to provide better airflow through the cooling array.Features:- OC mode : TBD MHz (Boost Clock); TBD MHz (Game Clock)- Axial-tech fan design features a smaller fan hub that facilitates longer blades and a slimmed down barrier ring that provides better airflow through the cooling array..- A 2-slot Design maximizes compatibility and cooling efficiency for superior performance in small chassis.- Dual ball fan bearings can last up to twice as long as sleeve bearing designs.- Auto-Extreme Technology uses automation to enhance reliability.- A protective backplate prevents PCB flex and trace damage.