Today I am reviewing the FM300 from Extech. The FM300’s primary operation is to measure and display formaldehyde concentration, air temperature, and relative humidity readings with date (year, month, day) and time simultaneously. The Extech FM300 is great for detecting formaldehyde from glue, paint, insulation/plywood/fiberboard, timber paneling/particleboard, cosmetics, shampoos, soap bars/body wash, lotions, toothpaste, etc.