American MarinePINPOINT Salinity Calibration Fluid, 53.0mS/1.026SG

This is very expensive saltwater. It works to calibrate your refractometer which you should do once a month. They charge way too much for this stuff, I think I should get into the business of putting NaCl&H2O into little bottles and selling it for a ton of money, that would be awesome!!!!!!!!!!

I wish the opening fit their probe and that more solution was provided.

really overpriced but needed to calibrate salinity probe

Worked well to calibrate refractometer

This works great for calibrating my refractometer. BOTH of my refractometers were off

Works great

Very good product

Not what it was suppose to be. not even close on the reading it list on the bottle, and i checked it with two different digital testers.