The MDM-21SH003B is a 21-contact Micro "D" metal shell socket connector designed for reliable signal and power transmission in aerospace and industrial applications. It features gold-plated copper alloy crimp contacts with a maximum contact resistance of 8 milliohms, an aluminum shell with yellow chromate/cadmium over nickel finish, and liquid crystalline polymer insulation. The connector is rated for 3 A maximum current per contact and 600 VAC dielectric withstanding voltage at sea level (150 VAC at 70,000 ft altitude), with insulation resistance exceeding 5000 megohms. It withstands thermal shock from -55 °C to +125 °C, physical shock of 50 g (3 axes, 6 millisecond sawtooth pulse), and vibration of 20 g across 10–2000 Hz for 12 hours, with a durability rating of 500 mating/unmating cycles. This connector is ideal for avionics, military equipment, and harsh-environment systems requiring compact, high-density interconnections with superior environmental protection.