One: It smells very natural stone smell, smells the smell of quartz stone, and adds formaldehyde-containing glue. Good quartz heater element are made of environmentally friendly materials. The bad pipe has a strong formaldehyde smell, and the price of this quartz tube can not be selected.
Two: Is there a pore on the surface?
Three: the gap at the joint.
Four: The scratch is deep and obviously unqualified, the key or the pencil sharpener.
Five: The stone powder is simply dropped to be unqualified.
Sixth: Those who have cut open and cracked are unqualified, and cut the upper edge of the face.
