Features: Durable clear plastic hydrometer. Accurate and easy to read. Designed for use in warm water aquariums (18-28C). Readings are temperature-corrected specific gravity units which range from 1. 000 - 1. 030 specific gravity 0-40 salinity ppt. It is for optimum to be put into below 6" deep water, so it can avoid the error from the oil slick. Fit for brackish and marine aquariums. Perfect for testing both salinity and specific gravity of your brackish and marine for tank. The easy-to-read swing-arm pointer and for extra wide stable base provide an accurate test result. Specifications: Material: Plastic Color: Clear (shown as pictures) Size: 9×12×1.5cm/3.54×4.72×0.59in (Approx.) Shape: Square Measuring range: 1.000-1.030 Salinity range: 0-40 Quantity: 1 PC (other accessories demo in the picture is not included) Package Includes: 1 x Salinity Hydrometer note: 1.Transition: 1cm=10mm=0.39inch 2.Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. 3.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you!