The 53-77-2G is a Thermalsil III thermally conductive silicone rubber insulator designed for TO-220 package applications, providing electrical isolation while enabling efficient heat transfer between components and heat sinks. This material is composed of a silicone elastomer binder with thermally conductive filler and is reinforced with glass cloth to resist tearing and cut-through from burrs on transistors or heat sinks. The insulator measures 17.50 mm × 14.27 mm with a thickness of 0.152 mm (0.006 inches) and features a gray-green color, eliminating the need for grease application while conforming to mounting surfaces under clamping pressure. Key electrical properties include a dielectric breakdown voltage of 26.3 × 10³ volts/mm and volume resistivity of 5.7 × 10¹5 ohm-cm, with thermal conductivity of 0.92 W/m·°C and service temperature range from -60°C to 180°C. This product is ideal for power electronics, voltage regulators, and thermal management applications where reliable electrical isolation and heat dissipation are critical.