NOYAFA Portable Formaldehyde Detector Indoor Air Quality Monitor HCHO and TVOC Monitor with Audible Alarm LED Indicator for Home HVAC System Using chip to accurately detect and concentration of formaldehyde(HCHO) and total volatile organic compound(TVOC). Precision air quality features rounded shape, glossy surface, compact and lightweight, easy to carry around. Super easy to operate, long press button to on, wait for a 180s countdown, and it will automatically HCHO and TVOC contents. Easy to read, 3-color LED indicator shows you level of TVOC - bad, normal, good. Immediately send out audible and visual alarm if concentration of HCHO and TVOC exceed normal level. Note: *Batteries not included. *Under normal battery level, unit will enter standby mode after 30 minutes if there is no operation taken. *Under low battery level, unit will enter standby mode after 5 minutes if there is no operation taken. Specifications: Unit: mg/m³ Item Size: 13.5*4.3*2cm / 5.31*1.69*0.78in Color: White Package Size: 16.5*9*3.2cm / 6.49*3.54*1.25in Package Weight: / 3.1oz Formaldehyde Dectection : 0.000~2.888mg/m³ Item Weight: 51g / 1.79oz TVOC Detection : 0.000~9.999mg/m³ Supply: 2pcs 1.5V AA Batteries (NOT included) Material: ABS Brand: NOYAFA Packing List: 1 * Formaldehyde Detector 1 * User Manual(English) Using advanced chip to accurately detect and monitor the concentration of formaldehyde(HCHO) and total volatile organic compound(TVOC). Super easy to operate, long press the button to power on, wait for a 180s countdown, and it will automatically monitor the HCHO and TVOC contents. Precision air quality monitor features rounded shape, glossy surface, compact and lightweight, easy to carry around. Easy to read, 3-color LED indicator shows you the level of TVOC - bad, normal, good. Immediately send out audible and visual alarm if the concentration of HCHO and TVOC exceed the normal level.