Generally, Tian Yang can be seen in the market, but the quality of personal experience in Tian Yang is even worse, with three years for the host and one year for the monitor.

Tian Kai is generally a customized product for the education industry or enterprises. There is generally no retail in the market, and the function is simple, but the quality is still good.

Tian Kai is rare now, and the function of Tian Kai is similar, but the configuration seems to be higher!