GN 8170 indexing plungers are intended for use in hygienic areas and meet hygienic requirements on the knob side. Wipers between the knob and the threaded body as well as the sealing ring between the threaded body and the housing keep the mechanics on the knob side sealed. The high surface quality (Ra < 0.8 μm) and the free of dead-space mounting prevent dirt from adhering and facilitate cleaning.