LBS-PTW is a sophysticated peltier temperature control water circulation system that can be connected to any type of water-jacketed UV-Vis or Fluorescence Cell Holder. The LBS-PTW temperature control process is capable of heating or cooling any cell holder from a minimum temperature of 20 C to a maximum of 60 C with an accuracy of +/- 0.1 C The system electronic control includes a touch screen display and a RS-232C interface for the comunication with existing UV-Vis or Fluorescence Instrument Software.