1、Automatic Detection: The seawater hydrometer can be read inside and outside of fish pond and tanks and automatically detects the specific gravity of water samples. 2、Easy to Operate: The seawater densimeter is used at a depth of 15cm (6 inches) to avoid errors caused by inhaling the oil film on the water surface. 3、Keeps Clean: Keeping your hands clean when using the aquaculture seawater densimeter will prevent contamination of the seawater in the fish pond. 4、Accurate Readings: The ocean hydrometer is easy to read and accurate to ±0.002 specific gravity units and gives accurate readings in fish pond at temperatures between 20‑30°C. 5、Safe Material: Sealevel automatic hydrometer is made of high quality transparent plastic material, accurate, durable, and easy to read your marine aquarium's salt level and specific gravity.