Double walled units having outer chamber of mild steel duly painted and inner of Stainless Steel. Temperature is controlled through a Microprocessor Based PID Digital Temperature Indicator-cum-Controller with an accuracy of +0.5oC. Carrier to hold bottles (6No.s of Size : 60mm dia x 200mm depth). 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.