The 188399-1 is a 2mm Hard Metric PCB mount connector featuring a receptacle housing with pin contacts, designed for vertical board-to-board interconnection applications. It is part of the Z-PACK 2mm HM interconnection system and provides 154 positions across 5+2 rows (rows A, B, C, D, F, Z, E loaded) with a module length of 50.00 mm. The connector incorporates ground return shielding, gold-plated mating contacts (30 µm), and phosphor bronze contact base material with tin-lead over nickel termination plating, ensuring reliable signal transmission and durability. The housing is constructed from polyester GF material with UL 94V-0 flammability rating and is always EU RoHS compliant. This connector is ideal for high-density backplane and midplane applications requiring robust, shielded interconnection with multi-purpose center polarization.