I have been engaged in the research of automobile safety technology for nearly 20 years, especially focusing on the active safety technology of automobile. At present, a vehicle active safety technology "vehicle multi-function rollover determination system and automatic rollover prevention device" has been granted the invention patent of the United States and China, the Chinese invention patent number is cn201110072592.4, and the American invention patent number is us 8935048 B2. I have spent nine years in the research on the superhard of chain saw files and have achieved gratifying results. The hardness of xliw has reached HRC70, and its quality has exceeded any brand at present. Compared with international famous brand Steele: one xinliwei is worth two Steeles