Littelfuse low cost interchangeable glass encapsulated thermistors are manufactured using super stable, precision NTC chips which are hermetically sealed in a glass (DO-35 diode style) package. The result is a device which exhibits excellent long term reliability and stability even when subjected to severe environmental or thermal conditions. They are well suited for uses where their interchangeability eliminates the necessity for costly individual circuit calibration. Their uniform dimensions and axial lead configuration make them especially suitable for use with automatic insertion equipment.