56-77-8G is a mica insulator designed for TO-220 package semiconductor devices, providing electrical isolation and thermal management. It features a maximum operating temperature of 550°C, dielectric strength of 172 × 10³ volts/mm (4500 volts/mil), and a dielectric constant ranging from 6.5 to 8.7, making it suitable for high-voltage applications. The insulator has dimensions of 18.93 mm × 13.84 mm with a thickness of 0.05–0.10 mm, and exhibits excellent thermal conductivity of 0.528 Wm?¹°C?¹ and high volume resistivity of 10¹5 ohm-cm. This RoHS-compliant component is commonly used in power electronics, voltage regulators, and thermal interface applications where reliable electrical isolation and thermal performance are critical.