4 oz. Calibration (Buffer) Solution Kit. 4 fl oz (each)
4 oz. Calibration (Buffer) Solution Kit. 4 fl oz (each) at HorticultureSource.com -
4 oz. Calibration Solution Kit. Contains One (1) 4 oz. bottle pH 4 Calibration Solution. One (1) 4 oz. bottle pH 7 Calibration Solution. One (1) 4 oz. bottle 1382PPM Calibration Solution. For use with the 24-7 Nutrient Monitor.