Incubation shaker CERTOMAT® Tplus is suited for the growth of bacteria, yeast, insect and plant cells in a temperature-controlled environment from 10° C below ambient temperature up to 70° C. Also available is an optional illumination unit for growth of photosynthetic organisms. CERTOMAT® Tplus is programmed via touch screen to operate at defined speed and temperature plus illumination. 20 programs, each consisting of four steps and one pre-step, can be defined and stored. The menue language can be selected by the user. CERTOMAT Tplus units can be stacked three units high in order to save valuable lab space. Due to the patented adjustable mass compensation system, all three stacked units can be run at maximum speed even when fully loaded.