The 20Kva stabilizer in relay type requires more stable control board and relays to work properly. Otherwise the instant big current easy to broken relay including turn to black or directly burnt. YIYEN’s technical advantage is that adopt MCU controlled PCB board, our response speeds up to 60MS namely 3 cycles, as you know detect voltage different already takes 20ms. And another key point is that our relay is customized. The silver contact is different from normal products over the market. And we have approved the longer service life by 200 hours non stop aging testing at our factory. So above development mainly reduce our failure rates for big capacity stabilizer from 10K to 20K.