Service Description: We will mail you a self-testing kit (containing a 5-in-1 testing box for formaldehyde, TVOC, PM2.5, humidity, and temperature), along with a detailed illustrated instruction manual. After you conduct the test, take photos and upload the results. We will provide an improvement suggestion report (e.g., ventilation plan, activated carbon placement, etc.). Testing consumables are disposable and suitable for apartments of 20-100 square meters.