MDM-21SH001B is a 21-contact Micro "D" metal shell socket connector designed for reliable interconnection in aerospace and industrial applications. The connector 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 for contacts size 9 to 100. It supports a maximum current rating of 3 A and a dielectric withstanding voltage of 600 VAC at sea level (150 VAC at 70,000 ft altitude), with insulator resistance exceeding 5000 megohms minimum. The connector is rated for thermal shock from -55°C to +125°C, physical shock of 50 G's on 3 axes, vibration up to 20 G's (10-2000 Hz for 12 hours), and 500 mating/unmating cycles at 500 CPH maximum, making it suitable for demanding military, aerospace, and industrial control systems requiring robust signal and power distribution.