Noctua has annouced a new product for its low profile NH-L9i and NH-L9a CPU coolers. The NA-FD1 is a multi-piece fan duct meant to help direct the fresh air from outside the case to the heatsink while reducing the recycling of hot air from within the case. It is composed of multiple Ethylene-Vinyl Acetate foam spacers that you can stack on top of the CPU cooler.
There is a total of 7 foam spacers with heights of 3mm, 4mm, 5mm, 6mm, 7mm, and 10 (x2) mm. It is compatible with all NH-L9 coolers, including both AMD and Intel versions, and all Chromax versions. It will also be compatible with future NH-L9i-17xx and NH-L9i-17xx Chromax coolers. All the spacers add up to a total 45mm of height abover the cooler (All NH-L9 are 37mm tall). Noctua claims that the fan duct can help reduce CPU temperature up to 5°C.