These double walled units have outer chamber of M.S. sheet duly painted and inner of S.S. Temperature range from 5°C above ambient to 90°C is controlled through a PI Digital Temperature Controller with an accuracy of + 0.5°C. An air circulation fan is also provided to ensure temperature uniformity. A carrier to hold bottles (6 in number of size 60 mm. dia x 200 mm. depth) can be easily place on the rotor. The carrier rotates at a variable speed of 2 to 16 rpm. Viewing glass window in the door allows inspection of the specimen inside the chamber. To work on 220/230 volts A.C.