Now Hiring those who truly care!  Click here to apply.

M-Geo Style Thermocouples

Products / Thermocouples / M-Geo Style Thermocouples

Metal sheath or mineral insulated (MI) style thermocouples are used in applications that require resistance to the harsh environment and temperatures for consistent readings.

All of our magnesium oxide insulated thermocouples, commonly referred to as MgO thermocouples, meet the special limits of error tolerances of ASTM E230 Tale 1.

We stock multiple diameters, sheath materials, and calibration types to meet your specific needs.

Build a Custom Thermocouple

M-Geo style thermocouples are insulated thermocouples produced by GeoCorp.
Contact us for more information or to get a quote.

Product Details

ANSI Calibration Types

  • Type K
  • Type J
  • Type N
  • Type T
  • Type E
  • Type R/S

Element Options

  • Single
  • Duplex


1/25″, 1/16″, 1/8″, 3/16″, 1/4″, 5/16″, 3/8″ and 1/2″
Call for metric availability.


Magnesium Oxide (MgO)

Hot Junction Styles

Ungrounded Junction
Thermocouple junction is separate from the welded external sheath end
Grounded Junction
Thermocouple junction is welded into the end of the external sheath
Exposed Junction
Thermocouple junction is exposed and butt-welded together

Termination Options

  • Thermocouple connectors & accessories
  • Transition to leadwire with metal relief spring
  • Stripped bare leads
  • Connector heads

Sheath Materials

  • Inconel 600
  • 304 stainless steel
  • 310 stainless steel
  • 316 stainless steel
  • 446 stainless steel
  • Other options available