Toothed steel grating is very common in people's production and life. During use, since the toothed steel grating is directly exposed to the air, it is easily affected by acid-base corrosion and o...
The well cover is also called "ditch cover", "manhole cover", "ditch cover", "the manhole cover was originally made of cement, and it is easily damaged in the normal use of the middle ditch. Later...