The Ade Advanced Optics Dual Scale 1.0 to 1.070 S.G. Salinity Refractometer is perfect for checking the salt level in your aquarium or seawater tank. With one scale that ranges from 0 to 100 ppt and the other that ranges from 1.000 to 1.070, this refractometer provides accurate and easy-to-use results. The sturdy design and compact size make it convenient to carry around and use, while the ATC feature ensures accurate and consistent readings. The 2 Year – No Hassle – Free Replacement Guarantee ensures that you can purchase with confidence.