Shield machines are indispensable when it comes to large-scale tunnel projects such as urban subways, mountain tunnels and sea crossing tunnels. 

Large shield machines can even reach five or six stories high and more than a decade ago, shield machines depended on importing equipment. 

Now, the "made in China" shield machine has been exported to 25 countries and regions globally. 

The machine has been ranked number one in sales for four consecutive years, with an accumulated tunneling mileage of more than 2,600 kilometers.  

Sun Xutao is in charge of a major expressway project for Beijing's East Sixth Ring Road, and the largest made-in-China shield machine is his closest companion. Take a look.