The Cooper-Atkins 5029 Probe measures Temperature and Relative Humidity.   It is an accessory for the MFM300.

Features:
Technology Base: Thermistor, Humidity sensor
Temperature Range: -40 to 185° F (-40 to 85° C) ±0.3%of reading
Humidity Range: 0 to 99%RH Accuracy:±2% RH
Shaft Length: 6"
Tip Diameter: .25" shaft & tip diameter
Cord Length: 6'
Weight: 6 oz as packaged (card and clamshell)
Warranty: 1 Year