Mitsubishi Heavy Industries Compact Ceiling Cassette Air Conditioner systems At only 258mm high, the FDTC series is one of the most compact ceiling cassettes on the market, allowing for easy installation in spaces with minimal roof space.  Optional motion sensor offers an energy saving solution by monitoring activity in the room and automatically switching to energy-saving mode at times of low activity. Fascia panel available in both honeycomb and grid design – see brochure for more info.