Formaldehyde gas detector, can detect the new world health organization level of 0.08 ppm average for 30 minutes. Measuring gas: formaldehyde (HCHO) in air. Detection range: 0-0.4 ppm (0.005 ppm/digit). Detection time: 30 minutes (1,800 sec.). Detection principle: photoelectric photometry method. Display: digital LCD. Operating temp. and humidity: -10 ~ 40°C , below 90% RH. Dimension: 3.35 x 7.48 x 1.57 inches. Weight: 500 g, 17.6 oz.