The S series, which are manufactured by Hitachi, are wall mounted, room air conditioners that have been developed to provide efficient, and reliable quality working performance. They have a compact design with heating and cooling capacities that ranges from 1.8 kW and up to 4 kW. It features an internal cleaning function that automatically controls the growth of mould, and as well as eliminating dust build-up at the micro mesh stainless filter. It operates with sound levels as low as 22 dbA.