These are basically miniature Thermoelectric Solid State Systems, designed on the principle of peltier effect. In many situations in day to day laboratory analysis, need of analysis at subambient temperature arises. The lab chemist has to use either an elaborate and bulky compressor based cooling system or use ice. Both these options have their own disadvantages.
These Systems are simple, sturdy & occupy very small bench space. No compressor hence no noise, no vibrations. No Ice, hence the working is not messy. All Solid State design, no moving parts, virtually maintenance free.
These systems are suitable for Cold Tests, to carry out Titration at subambient or at elevated temperatures, to maintain Cell Holder Temperature, viscosity measurement, to cool vials & test tubes etc.