Refractometer can automatically compensate temperature when ambient temperature changes, the deviation, you can get the accurate results fast and easier. Only need 2 or 3 drops of solution and wait for few seconds, then you get the accurate results. Features - Color: As shown. - Size: 19.50X4.00X4.00cm/7.66X1.57X1.57 inch. - Material: Metal, rubber. - Measuring range: 0-100%. -Note: cloth is random color - The build-in automatic temperature compensation feature makes it get consistently accurate reading, no need to control the liquids temperature deliberately, just make sure it's at room temperature ( during 0-25 degree centigrade) . - Just need to take of your liquids on the prisms and hold the refractometer to the light, then look through the eyepiece, you can get the reading. And the refractometer shows result by ° system. No need table and no waste - Measure salt water or of water, great for aquariums and marine monitoring - The instrument is resistant to abrasion and corrosion, can be used to measure corrosive liquid - It is simple in design, but it's practical to use, which will give you a good use experience Package list: 1 x Refractometer 1 cloth 1 x straw 1 x English manual 1 x screwdriver 1 x packing box