The FN-A12x25 uses an ultra-tight tip clearance on the edge of the blades, running only 0.5mm from the inside of the frame, requiring new engineering techniques to be employed. This helps to reduce back pressure by allowing the air nowhere to go other than forwards, affording a more efficient fan. There's also flow acceleration channels, a solid steel and brass hub structure, stepped inlet design and loads of other technologies employed to ensure this fan is as good as currently possible.