The GSC3 designation does not appear explicitly in the provided SPEC_CONTEXT, which contains detailed specifications for SMG and STG series fuses from Ferraz Shawmut. The context includes fast-acting SMG fuses with glass bodies and optional 1-1/2" axial leads, rated from 1/10A to 10A across 250VAC, 350VAC, and 125VAC, as well as time-delay STG fuses with similar construction. Without a direct SKU match for GSC3 in the specification tables or product descriptions provided, the exact electrical ratings, insulation resistance class, and size designation for this specific part number cannot be reliably determined. The datasheet context suggests GSC3 may be part of a broader fuse product family, but the specific technical parameters for this SKU are not clearly identified in the available material.