Sunbeams appliances has manufactured air - to - air heat exchangers which are useful with electrical and electronic panels where internal electric components can withstand and function with slightly above ambient temperature and where humidity is not a factor. Theses exchangers are of two types such as - aluminum fin type and heat pipe type. The main features of these air-to-air heat exchangers include - closed loop design, inside as well as outside installation is made possible, easy maintenance, choice of side top, front inside and outside, vertical and horizontal mounting are available, 100% functionally tested, dc voltage available if required and custom built enquiries are also entertained. All the machines after assembling are tested on specially designed test rig at full load. The exchangers have the capacity ranging is from 5 watts /º c to 110 watts / ºc.