The IT series probes are used for implanting in semi-solids and tissue with a guide needle. Also for immersion in various solutions and rectal temperatures of small animals. Totally sheathed in chemical resistant Teflon for added durability. Max Temp. 150°C. Isolated. The number designates needle gauge size.
 
IT-14: Flexible Implantable Temperature Probe, 14 Gauge. 0.050" diameter. Time Constant 0.3 secs. 3 ft. lead length.

IT-18: Flexible Implantable Temperature Probe, 18 Gauge. 0.025" diameter. Time Constant 0.1 secs. 3 ft. lead length.

IT-21: Flexible Implantable Temperature Probe, 21 Gauge. 0.016" diameter. Time Constant 0.08 secs. 1 ft. lead length.
 
IT-23 is for ultra fast measurements and for use on micro-size specimens. The sensor lead is only 0.009" diameter. Implantable with 23ga. guide needle. Max. temp. 150°C. Time constant 0.005 secs. 3 ft. isolated lead.
 
IT-1E is the same as the IT-18 except the sensor bead is exposed. This probe combines the ultra-fast response of IT-23 with the Teflon sheath strength of IT-18. Time constant .005 secs. 3 ft. isolated lead.

IT-24P: Flexible Implantable Temperature Probe, 24 Gauge, Polyvinyl Insulation