Air Quality Monitor, Air Meter for Testing HCHO TVOC, Indoor Formaldehyde(Hcho) Detector, Portable, Simple to Use, Great… Price: 19.99 (as of 02/10/2022 14:46 PST- Details)

Accuracy detection: Test indoor Formaldehyde(HCHO) and TVOC Volatile Organic Compound Gas, through the principle of semiconductor gas sensors which make it more accuracy.
One key operation: The palm-sized portable air detector is easy to carry. Simplified design with one key operation make it easy to use.
Sound and light alarm: The LED lights red, yellow and green respectively represent : Poor, normal and excellent. When the air quality is poor, the buzzer will alarm.