Description: Features: Designed for saltwater marine aquariums. Built-in thermometer measures both water temperature and salinity. Green indicators show the ideal range of water temperature and specific gravity for most saltwater aquariums. Easy to use: Place the hydrometer into water and allow it to float freely. Available in two sizes: L: Approximately 26.5 cm (10.43 inches) in length S: Approximately 20 cm (7.87 inches) in length Measuring range: 1.000–1.040 Temperature range: 0–40°C (32–104°F) Specifications: Material: Glass Color: Transparent Length: S: Approx. 20 cm (7.87 inches) L: Approx. 26.5 cm (10.43 inches) Weight: S: Approx. 40 g L: Approx. 60 g Measuring range: 1.000–1.040 Temperature range: 0–40°C (32–104°F) Notes: 1. Please allow for a measurement tolerance of up to 1 cm due to manual measurement. 2. Monitor settings may cause slight color variation between the image and the actual product. Package includes: 1 x Aquarium Hydrometer (S or L)