Handheld Refractometer Sugar Concentration Meter Densitometer 0‑50% Sugar Tester Meter Condition: Item Type: Sugar Tester Meter Material: Plastic + Stainless Steel How e: Open the cover and wipe the prism carefully with a soft cloth.Take a few drops of the solution to be measured and place them on the prism. Gently close the cover plate to avoid bubbles and make the solution spread all over the prism surface. Aim the instrument at the light source or bright place, observe the field of view through the eyepiece, turn the eyepiece to adjust the hand wheel, make the blue and white dividing line of the field of view clear.The scale value of the boundary is the concentration of the solution. Measurement Range: 0-50%