The MS603XP0601A is a marking insulator strip designed for sub-mounting beneath terminal blocks to provide electrical insulation between the terminal block and chassis while offering a surface for terminal identification. This Series 603 strip is manufactured from XP material (paper/phenolic resin laminate) with UL 94HB flame resistance and features printed terminal designations numbered 1, 2, 3, and so on (01A print style). The strip dimensions include a width (C) of 1.88 inches, a depth (D) of 0.63 inches, and a height (E) of 0.59 inches, with mounting holes of 0.23 inches diameter and text height of 0.13 inches. These marking insulator strips are commonly used in industrial control panels, switchboards, and terminal block assemblies to clearly identify terminal connections and maintain proper electrical isolation between conductive and non-conductive surfaces.