It's hard to say how accurate the absolute measurements are, but they seem to be compared from room to room, area to area. This seems to be one of the best options when determining the dustiest areas of a building, or before and after installing an air filtration system.
Thermometer B.Well WF-4000 white
57 Review
Room temperature and humidity sensor Aqara Temperature and Humidity Sensor white
25 Review
ICQUANZX LCR-T7 Transistor Tester: Advanced TFT Diode Triode Capacitance LCR ESR Meter
14 Review
VIVREAL 4 In 1 Stud Finder Wall Scanner With LCD Display - Center Finding Beam Finder And Sound Warning For Wood, AC Wire, And Metal Studs (Black/Silver)
24 Review
β Stainless Steel L-Square, Size 3-Inch x 4-Inch, Zona 37-434
8 Review
π CAMWAY 6 Inch Digital Caliper with LCD Display, Electronic Vernier Caliper, 150mm Stainless Steel Feeler Gauge, Plastic Digital Caliper Set for Zero Setting Inside/Outside Diameter, Depth, and Step Measurement Tool
3 Review
π Johnson Level and Tool 400EM-S 12-Inch Heavy Duty Metal Combination Square for Professionals, with Inch/Metric Measurements, Silver - 1 Square
8 Review
Kapro 307-08-TMS Try And Mitre Layout And Marking Square With Stainless Steel Blade, 8-Inch Length
18 Review