Single wavelength colorimeter with reagents and carrying case. Lithium rechargeable battery.  LED light source with silicon photodiode and interference filter. Ozone uses Indigo Blue method, range 0-4.0ppm with 0.04 detection limit. Reagents for 100 tests

Auto self-calibration; resolution to 1 mV; range -999 tpo 999mV, accuracy +/- 4mV;  Four 3V CR-2032 button batteries.  pH probe included.