Apera Instruments Salt20 Pocket Salinity Tester Kit is built for professional salinity measurement of general water soliutions including pools& spas agriculture education environmental monitoring etc Range 0-10 0 ppt Accuracy 1% F S 1 point auto calibration 0 to 50˚C auto temp compensation The BPB (Brush-Resistant Platinum Black) sensor adopts Apera's special processing technology which minimizes electrode polarization expands measuring range and increases firmness of the electrode hence ensuring a much higher accuracy and consistency in a wide-range salinity measurement than traditional stainless steel electrodes and is easy to clean The large LCD screen has ppt/temp value dual display and indications of completed calibrations and stable readings Practical functions to make your salinity testing easier and more reliable 2-point auto calibration 0 to 50˚C auto temp compensation Self-diagnosis with out-of-range and low battery warning Complete kit Salt20 meter 1 bottle of calibration solution AAA batteries and a lanyard all in a portable carrying case IP67 water-resistant Up to 1000 hours of use powered by 4 AAA batteries Low power alarm and auto power off in 8 min if no operation The product is CE and RoHS certified and is manufactured under an ISO 9001 2015 certified quality system