Air duct with one or more fins

A computer system comprising:

• a chassis having a front, a back, two side chassis walls, and a bottom chassis wall;
• a board connected to the bottom chassis wall, the board having a plurality of slots facing up from the bottom chassis wall, each slot of the plurality of slots accepting a component;
• and
• an air duct connected to the board and positioned over the plurality of slots, the air duct including:
• a housing for directing air over the plurality of slots, the housing including side housing walls that connect the air duct to the board and a top housing wall connected to and extending between the side housing walls;
• and
• a plurality of fins extending from the top housing wall towards the plurality of slots, each fin of the plurality of fins being arranged on the top housing wall such that each component accepted in the plurality of slots is positioned between adjacent fins of the plurality of fins,
• wherein each fin of the plurality of fins is a quadrilateral with a declined front edge and includes a projection extending down from a bottom of the fin.