The MDM-21SH041B is a 21-contact Micro "D" metal shell socket connector designed for reliable interconnection in compact electronic assemblies. It features a gold-plated copper alloy contact material with crimp termination, maximum contact resistance of 8 milliohms, and an aluminum shell with yellow chromate/cadmium over nickel finish. The connector is rated for 3 A maximum current per contact and provides 600 VAC dielectric withstanding voltage at sea level (150 VAC at 70,000 ft altitude), with insulation resistance exceeding 5000 megohms. It operates across a thermal shock range of -55°C to +125°C, withstands 50 g physical shock (3 axes, 6 millisecond sawtooth pulse) and 20 g vibration (10–2000 Hz for 12 hours), and is rated for 500 mating/unmating cycles at up to 500 cycles per hour. This connector is commonly used in aerospace, military, and industrial applications requiring compact, high-reliability interconnections in harsh environments.