(under subclass 317) Indicator, sampler, or inspection feature wherein the means shows deterioration, proper or improper positioning, or location to aid in sealing to oppose the flow of fluid.
SEE OR SEARCH CLASS
73, Measuring and Testing, for a detailed structure or method for measuring or testing,
7+, for a measurement or test made involving any one or any combination of operations of abrasion, milling, rubbing, or scuffing.
116, Signals and Indicators, for a specifically recited and detailed mechanical device for giving signals of the nature of an alarm or indicator that appeals to any one or more of the senses and combined with nominal apparatus structure from other classes,
208, for a wear indicator for an element having means to convey information to one of the senses.
