... reputation. all customers like our price and quality.there are two types, Grade "A" or Grade "B" ,as ... pick up the drops of liquid. 2, before reading the bubbles out of the tube, filled with liquid ... inside. 3, need to have two readings, reading for the first time must first adjust the liquid ... level under scale 0 0 or scale. 4, when reading, concave bottom line of sight, scale, the liquid ...