SunGrow Aquarium Refractometer, 7.6 Inches, Measure Salinity of Water, Remarkable Accuracy, Includes Calibration Tool, Ensures Overall Health of Plant and Marine Life, Easy and Clear Reading

This is a great product and what was a fantastic price, disappointed it has doubled in price but still reasonable considering prices of similar items. Tested against more expensive refractometer and hydrometer and against one at lfs and is totally accurate and has stayed accurate since first calibration.

I paid for a Prime next day delivery but it took 3 days to arrive. The instrument is basic and not easy to focus.

Been using for several months and seems very accurate so far, much better than the plastic needle type hydrometer

I would get this fast before they realse how good it is and how cheap they are selling it. Arrived quickly and it is as good as units twice the price and better boxed than many of them. It is easy to calibrate and accurate, a total steal at this price.

I'm sure the product is absolutely lovely, but instead I got an empty box for for my £15

Was not accurate before or even after be recalibrated by myself and then local fish shop. Based on the many good reviews I may have got a bad one unfortunately but have now gone with another brand instead.

Fantastic value for moneyWould definitely recommend

Arrived on time and we'll packed small scratch on the plastic slide but does exactly what it's supposed to