INSULATED IMPLEMENT

摘要

An instrument wherein coatings of two different materials are disposed on external surfaces. The first of these coatings is selected to provide an insulating layer overlying at least a principal surface of the instrument, whereas the second is included to provide an indication of the likely remaining useful life of the insulating layer. The relative characteristics between the two coatings is selected so that when the visual appearance of the second coating progresses to a predetermined level, the insulating qualities of the first coating will still be satisfactory but approaching a point when the instrument has reached the end of its useful life, thus providing a ready and passive visual indication of the time when the instrument should be replaced.