1. Real time monitoring: Real time display of formaldehyde concentration, tvoc concentration, air humidity, and current time, fully understanding the air quality status. 2. Air quality assessment: Provides formaldehyde hazard assessment function to help users identify potential health risks in the air. 3. Historical data recording: Support historical data recording of formaldehyde concentration and tvoc concentration for better long-term air quality management. 4. Spatial average: Calculate the spatial average of formaldehyde and tvoc to help users evaluate air quality more accurately. 5. Formaldehyde removal calculator: Intelligently calculates formaldehyde removal time, cost, and required materials based on house area, house type, average formaldehyde content, and formaldehyde removal method. Alarm threshold setting: Users can set the alarm thresholds for formaldehyde and tvoc according to their needs. Once exceeded, the equipment will immediately sound an alarm to ensure indoor air safety. Calendar and time display: Display the current date, time, and humidity, providing convenient time management functions. Parameters: Product name:4 in 1 formaldehyde tester Product model:sfd-02 Screen material:2.4-inch tempered glass touch high-definition color screen Backlight: adjustable backlight brightness Charging method: usb type-c interface (5v/2a) Battery: 1000mah 1*lithium battery Language: chinese, english Formaldehyde parameters: Range: 0-2000 ppm Detection hardware: electrochemical sensor Preheating time: 5 seconds Tvoc parameters: Range: 0-10mg/m³ Testing hardware: Semiconductor sensors Preheating time: 120 seconds Classification of formaldehyde levels: Excellent: 0mg/m³ -0.08mg/m³ Good: 0.08mg/m³-0.1mg/m³ Mild pollution: 0.1mg/m³-0