Safe Material: Made of high-quality plastic, this clear aquarium hydrometer provides automatic, accurate, and readable measurements for saltwater tanks. Accurate, durable, and easy to read, it helps monitor your marine aquarium's salt level and specific gravity. Compact and waterproof design. Clearly Indicated Safe Zone: Features both salinity and specific gravity scales. The outer scale indicates salinity in PPT, while the inner scale indicates specific gravity. Suitable for brackish and marine aquariums. Ideal for testing both salinity and specific gravity in your brackish or marine tank. Easy to Read and Use: Equipped with an easy-to-read swing-arm pointer and an extra-wide, stable base for reliable results. Color: As shown in picture Size: Approximately 24 x 14.5 x 3 mm Packing List: 1 x Hydrometer