The choice of suitable tip style is one of the most important factors in choosing the right test probe. Many of the tip styles can be used for several applications. A basic classification can be made with respect to the geometry of the test points, such as pad, via, pin or posts. Furthermore, the test point can be differentiated by its size and surface condition (oxidised, clean or contaminated by residue from the soldering process). Depending on the DUT and test conditions, it may be necessary to try several tips styles and spring forces in order to find an optimal combination.