1、Product Structure Analysis: Fast measurement, accurate data, convenient use, wide application and complete equipment. 2、Adjustable Eyepiece: When salinity refractometer scale is not clear, you can gently rotate the eyepiece for adjustment. 3、Clear Reading: 0‑28% salinity refractometer has fast detection, accurate measurement, clear display and convenient use. 4、Cover Plate Function: The use of cover plate is to protect the prism and make the measurement more stable. 5、Calibration Screw: Drop distilled water on the prism and turn the zero adjustment screw to adjust the dividing line to 0% of the scale. Item Type: Refractometer Material: Plastic, Aluminum Color: As Pictures Shown Weight: Approx. 253g / 8.9oz Salinity: 0-28% Product Size: Approx. 17.2x4x4cm / 6.8x1.6x1.6in 1 x Refractometer 1 x Straw 1 x Lens Cloth 1 x Screwdriver 1 x Manual 1 x Plastic Box Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.