TDK glass-encapsulated NTC sensor elements for temperature measurement with flexible electrical insulation (the G1541, G1551 and G1561 series) have fast response, compact dimensionsm and high temperature resistance. In addition to the benefits of the glass-encapsulated NTCs already available for some time, they offer insulation with a specified voltage resistance of 500 V DC/1s in NaCl solution. This assured voltage resistance obviates subsequent insulation, e.g. with Teflon tubes, and simplifies processing so that the costs incurred are significantly reduced. They can even be used in highly constrained insertion situations, such as in sleeves.