The Automated Logic ALC/10K-2-RA-12" is a Rigid Duct Averaging Temperature Sensor that has 12" (0.3m) probe length. 

The Automated Logic Rigid Averaging Units feature closed cell foam to seal the probe insertion hole and absorb vibration. Mounting tabs allow for easy installation directly to the wall of the duct. All units have etched Teflon leadwires and encapsulated sensors to create a watertight package that can perform under real world conditions. Averaging probes should be used wherever there is a chance for stratified layers of hot and cold air. Averaging probes are made of 1/4” diameter stainless steel tubing. Rigid Averaging Units come standard with a 2”x4” steel J-Box but are also available with no box or the new BAPI-Box Crossover enclosure.