The 1-66400-1 is a Metrimate pin and socket connector designed for reliable electrical interconnection in metric-dimensioned applications. This connector features crimp-style contacts suitable for wire sizes ranging from 24-20 AWG (0.2-0.6 mm² and 2.03-2.54 mm² insulation diameter), with selectable gold/nickel or bright tin-lead contact finishes. The connector operates at a voltage rating of 600 VAC/VDC (UL/CSA) with a dielectric strength of 2000 Volts RMS and maintains insulation resistance of 5000 Megohms minimum. It is designed to meet IEC 440 V requirements and operates reliably across a temperature range of -55°C to +130°C. The connector's true metric dimensions with 5 mm contact centers, polarized housings made of UL-rated 94V-0 thermoplastic, and availability in multiple position configurations make it suitable for industrial control systems, telecommunications equipment, and general-purpose electronic assemblies requiring secure, repeatable connections.