Horiba Cardy Twin K+ Potassium Meter (C-131) - With extra solutions Measures Potassium (K+) in water, soil, plants food and other solutions Easily calibrate meter and measure samples. Measures in PPM. Measurement range of 39-3900 ppm. Easy measurement with only a few drops of sample. Agriculture Solutions LLC includes additional wash bottle and 125ml each of additional calibration solution. Comes with 1 year warranty with Agriculture Solutions LLC