Monitor and Record low differential pressures and temperature with the model DL7 Differential Pressure Data Logger. Unit includes an onboard thermistor for ambient temperature measurement. Sampling rates are user selectable from 0.04 seconds to 8 hours with First-in first-out or Fill-then-stop sampling options. Loggers can store up to 21,500 readings and operate totally independently from any external power supply with built-in lithium battery. Use Model DL200 Windows® software (sold separately) to quickly program the logger or upload data to a computer. The series DL7 logger is ideal for monitoring air duct velocity, testing and balancing HVAC systems, or verifying room pressure.