2. Feature Convenient to use: Light weight and small size, suitable for detection on site, and minimize the errors caused by long transportation; Standardized operation, and minimized manual errors; Real-time monitoring of ozone concentration in production process. Accurate Measuring: Scientific formulation, special techniques, and strict quality control; Research and development conducted under international standards and methods; Produced from imported materials, including color agent, buffer agent, spiking agent, and covering agent, etc; Standardized precise colorimetric cards specialized for colorimetric tubes; Double layers aluminum foil, preventing moisture and light.