Features: Precise PM2.5 concentration based on pre-calibrated sensors. Temperature measurement (C/F). Humidity measurement. Emoticon display. LCD backlight and red backlight alarm. Battery status, low power, auto power off. LCD size: 3 inches. Concentration expression grading: Yes. Low battery indication: Yes. Backlight: Yes. Specifications: PM2.5 (ug/m3): 0-100 (10ug/m3+10dgts). 101-400 (10%+30dgts). 401-500 (10%+50dgts). Temperature: -10 to 50 Degree Celsius 1C, 14 to 122F 1.8F. Humidity: 5 to 99 5%RH@30% to 80%RH; 8%RH@<30%RH, >80%RH. Power by 3.7V 1500mAh rechargeable polymer battery (Included). Color: White and Black. Product size: 75mm x 55mm x 130mm. Weight: 230g. Package Included 1 x NKTECH A25D+ Air Quality Detector. 1 x NKTECH TL-1 Screwdriver. 1 x MINI USB Interface Cable. 1 x English User's Manual. 1 x Carrying Bag.