A Cold Finger is a type of laboratory glassware primarily used in the sublimation. The main function of this equipment is to generate a localized cold surface that is critical to the process of sublimation. The term cold finger has been derived due to the equipment�s resemblance to a finger as a type of cold trap.
Commonly, a cold finger is used in the apparatus needed for sublimation, or it can be used as compact version of a condenser in either reflux reaction or distillation process. The device generally consists of a chamber in which a coolant fluid - cold water or perhaps something colder - can enter and exit.