They have: construction characteristics that are the same as those of the PL series at 85°C, with the exception of the second system in cascade high reliability by the machine, with a new (CFC- and HCFC-free) refrigerating circuit design using specific components for low temperatures (up to -50 °C), a truly innovative fluid (compatible with low-viscosity P. O. E. oil), that allows very low evaporation temperatures even in critical environmental conditions with T > +35 °C they come standard with a monitoring, recording and control system, KWS NEW ICE AGE CONTROL®; this is a really innovative control for the cryobiology and very-low-temperature sectors, offering an optimal machine-user interface and a series of advantages for usage and technical support; above all, it offers special functions that turn it into a unique solution (see KWS Premium Line at -85° C); in addition: optional 4,000 VA voltage regulator; in case the voltage regulator is present, the COMPRESSORS ARE GUARANTEED FOR 3 YEARS. For all this, KW K40.PLL Premium Line represents the -45 °C / -50 °C version of the PL at -85 °C