Check the listing for details. Fish Tank Aquarium Salinity Testing - SR Aquaristik Saltwater Refractometer. Condition: New. Listed at 29.98 USD. SR Aquaristik Saltwater Refractometer Fish Tank Aquarium Salinity Testing Simple and Accurate Salinity and Specific Gravity Testing. Tired of trying to find the perfect light to properly read your test results? With the new SR Aquaristik saltwater refractometer, that is no longer an issue. Simply press down on the illumination button and receive sharp, clear test results. Temperature compensation ensures test results are accurate within +/- 1ppt/0.001 specific gravity. Calibration is quick and easy with the included calibration solution and screwdriver. What's Included in the kit? Built-In Light Source for More Accurate Testing Pipette Protective Carrying Case Screw Driver for Calibration Adjustable Focusing Eyepiece Salinity Calibration Fluid - Calibrates to Sg 1.026 (35Ppt) Three-year warranty Replacement lights are available and sold separately Calibration Instructions Place a few drops of the solution on the glass and close the lid. Looking through the unit, depress the light illumination button & turn the screw until the unit reads sg 1.026 (35ppt). Screw the cap back on your calibration solution for storage. It is important that the cap is on tight or water will evaporate and ruin the integrity of the solution; giving false readings. RETURN POLICY We want you to be happy with our products! If you are not 100% satisfied with your purchase, you may return it for a replacement or a refund of the full product cost. It's part of our no-risk customer guarantee!