While the Standard Kestrel 3000 w/ Relative Humidity is the model that has made Kestrel a trusted brand among firefighters. The 3500 model is a more feature rich meter includes an easy to read and waterproof PIG (Probability of Ignition)  and FDFM (Fine Dead Fuel Moisture) cards, Wet Bulb Temperature, altitude and barometric pressure. This fast and accurate device is a great options for firefighters looking for consistently precise measurements without the possibility of human error.