1[LCD BACKLIGHT DISPLAY] Portable ORP meter with LCD backlight display, it only takes a few seconds to read the readings on the digital display. 2[HIGH RESOLUTION] The measurement range is 19991999mV, the resolution is 1mV, the accuracy is 5mV, and 050 automatic temperature compensation. 3[HOW TO USE] Just immerse the probe of the ORP testing pen in the water to quickly detect the redox potential value of the water. 4[QUICK AND SIMPLE] This is a very useful tool when you need to test the water quality of pond, aquariums, swimming pools, aquaculture, spas, etc. 5[SMALL AND PORTABLE] ORP test meter, mini size, light weight, compact structure, high measurement accuracy, easy to use, high stability and reliability.1 x ORP Tester (Battery Not Included)1 x Screwdriver1 x Manual1 x Storage Box