Features: Using advanced chip to accurately detect and monitor the concentration of formaldehyde (HCHO) and total volatile organic compound (TVOC). Immediately sends out audible and visual alarm if the concentration of HCHO and TVOC exceeds the normal level. Super easy to operate: long press the button to power on, wait for a 180-second countdown, and it will automatically monitor the HCHO and TVOC levels. Easy to read: 3-color LED indicator shows the level of TVOC — bad, normal, good. Precision air quality monitor. Features a rounded shape, glossy surface, compact and lightweight design, easy to carry. Note: Batteries not included. Under normal battery level, the unit will enter standby mode after 30 minutes if there is no operation. Under low battery level, the unit will enter standby mode after 5 minutes if there is no operation. Specifications: Brand: NOYAFA Material: ABS Color: White Formaldehyde Detection Range: 0.000–2.888 mg/m³ TVOC Detection Range: 0.000–9.999 mg/m³ Unit: mg/m³ Power Supply: 2 x 1.5V AA Batteries (NOT included) Item Size: 13.5 x 4.3 x 2 cm / 5.31 x 1.69 x 0.78 in Item Weight: 51g / 1.79 oz Package Size: 16.5 x 9 x 3.2 cm / 6.49 x 3.54 x 1.25 in Package Weight: 88g / 3.1 oz Packing List: 1 x Formaldehyde Detector 1 x User Manual (English)