Diagnostic Psychrometer; Type Digital, In-Duct; Measuring Range -4 to 140 Deg F (Temperature), 0 to 100 Percent RH (Humidity); Sensor Type Precision Thermistor; Battery Type Alkaline; Display Type Backlight; Application HVAC/R System; Telescoping Probe Size 38 Inch; Battery Life 150 Hour; Includes Stabilizing Cone, Blow Molded Case