Feature: 1. [Plastic Material] Salt water salinity meter for fish tank is made of plastic material, which is strong and durable. 2. [Auto Detection] Aquarium glass saltwater hydrometer is lightweight and easy to use and automatically detects specific gravity of water samples. 3. [Accurate Reading] Aquarium hydrometer auto recognizes the level to get accurate reading both in the pond, in and out of the tank. 4. [Salinity Tester] Aquarium salinity tester tests salinity and specific gravity of fish tank, specific gravity range 1.000 to1.030, salinity range 0 to 40. 5. [Note] Crystallization of salt on the pointer will cause inaccurate readings If salt crystallizes in the hydrometer, soak the hydrometer in warm water or vinegar for 30 minutes, then rinse with water and air dry. Specification: Item Type: Aquarium Salinity Tester Material: Plastic Application: Aquarium Seawater Concentration Meter Specific Gravity Range: 1.000-1.030 Salinity Range: 0-40 Applicable Temperature: 20-30℃ / 68-86℉ . Package List: 1 x Aquarium Salinity Tester1 x Plastic Rod Note: Before using the hydrometer for the first time, fill it with warm water and detergent to clean the surface oil stains inside, which can be more accurate.