Feature 1Product Structure Analysis: Fast measurement, accurate data, convenient use, wide application and complete equipment. 2Adjustable Eyepiece: When salinity refractometer scale is not clear, you can gently rotate the eyepiece for adjustment. 3Clear Reading: 028% salinity refractometer has fast detection, accurate measurement, clear display and convenient use. 4Cover Plate Function: The use of cover plate is to protect the prism and make the measurement more stable. 5Calibration Screw: Drop distilled water on the prism and turn the zero adjustment screw to adjust the dividing line to 0% of the scale.SpecificationItem Type:RefractometerMaterial:Plastic,AluminumColor: As Pictures ShownWeight: Approx. 253g / 8.9ozSalinity: 0-28%Product Size: Approx. 17.2x4x4cm / 6.8x1.6x1.6in .wang-edit-text{ font-family:'Arial' !important; } .wang-edit-text table { border-top: 1px solid #000; border-left: 1px solid #000; } .wang-edit-text table td, .wang-edit-text table th { border-bottom: 1px solid #000; border-right: 1px solid #000; padding: 3px 5px; } .wang-edit-text table th { text-align: center; }Package List1 x Refractometer1 x Straw1 x Lens Cloth1 x Screwdriver1 x Manual1 x Plastic Box