The Middle Atlantic MW-4FT-FC is a thermostatically controlled integrated fan top that ships fully assembled. It. Includes four 4in fans, fan guards, and a proportional speed fan controller designed to increase fan life, reduce noise, save energy, and minimize dust build-up. This product is ETL listed in the US and Canada. Key features include a pre-assembled fan top with four 4in fans and proportional speed controller, fans that operate only when needed to conserve energy, reduce noise, and lower maintenance requirements. It is compatible with WR, WRK, MRK, VRK, VMRK, and DRK racks. Additionally, it. Includes a removable two-space service plate, allowing top removal without disrupting cable bundles. The fan top is constructed from steel with a black finish.