In order to obtain the fading statistics for the K fading channels, the equivalent process of the K process, i.e. the product process of a Rayleigh process and a Nakagami process, is utilized. The mapping relationship between the K process and its equivalent process is found by equating the arbitrary order moments of them. On this basis, the equivalent level crossing rate (LCR) of the K fading channels is derived first and followed by the derivations of the equivalent average fade duration (AFD). Also, the fading statistics of the K fading channels at low signal levels are given because the communications under the fragile radio link are very important for us to study. Finally, the numerical computations and analysis are presented.