The KT-78A is simply a low power version of the popular KT-76A transponder. The KT-78A peak power is 113 watts minimum while 200 watts for the KT-76A. The KT-78A was originally designed for low flying aircraft that operated in very local areas such as crop dusting (agriculture) applications. Both the KT-76A and KT-78A are 14 volt radios that utilize the same mounting rack and connector. Therefore, the higher power KT-76A is an ideal direct replacement for the KT-78A considering that the KT-78A has not been manufactured for many years and is therefore scarce on the used market.