The Q-Set allows a highly accurate and flexible positioning of a prism for different beam heights. The prism table allows an adjustment of the prism in three degrees of freedom about a common pivot point. In addition, a horizontal alignment is possible via the supplied rail (coarse adjustment) and the linear stage (fine adjustment). The mounting column with rod enables adjustment to beam heights 12-21 cm whereas the maximum height can be extended by using longer columns. An ideal area for the Q - set is, for example, together with another identical set in a prism compressor.