CM 690 III is a revolutionary update to the popular CM 690 II mid-towers. The exterior retains the curved metal mesh look the series is known for. The interior has been completely updated Â- the HDD/SSD combo cage can be switched between 3.5-inch or 2.5-inch drives by adjustable trays without any screw. There's enough room for a 240mm liquid cooling radiator at the top or front, 120mm in the rear & supports up to 9 fans, including 3 large 200mm fans for extreme airflow. & cleaning is hassle free thanks to the multiple dust filters at the bottom, top, & front. AIRFLOW  &9679; Top: 120/140mm fan x 2, or 200mm fan x 1 (optional) &9679; Front: 200mm fan x 1 (installed), or 120/140mm fan x 2 / 180mm fan x 1 (optional) &9679; Rear: 120mm fan x 1 (installed) &9679; Side: 120mm fan x 2 or 180/200mm fan x 1 (optional) Â- for CMS-693-KKN1 &9679; Bottom: 120mm fan x 1 (optional) &9679; HDD cage: 120mm fan x 1 (optional)    COMPARISON Â