Indexing plungers GN 817.5 allow highly accurate positioning, with the guidance made by the positioning bushings DIN 172 / DIN 179 with cylindrical bore. The actual indexing bore is fitted with positioning bushings GN 172.1 / GN 179.1 with conical bores. The conical shape of the indexing pin / the indexing bore makes the positioning virtually clearance-free and therefore highly precise. Type C is used for such applications where the plunger has to stay in its retracted position. To achieve this, the knob is rotated by 90° degrees after being retracted. A notch keeps the plunger in this position.