Precision masking is the process through which a specific area of a part is "masked off”, or protected, from the finishing process. Applying coatings often requires a masking step to prevent coating deposits on specific surfaces. For example, sometimes the mating surfaces of two parts need to be masked for grounding purposes or for bearing surfaces. Threaded holes or bolts need to be masked to prevent powder coating from filling the threads. Sometimes there are creative reasons for masking, as well. Common materials used are high temperature tapes, silicone plugs, caps, and custom silicone masks.