1-120521-1 is a 64-position mezzanine receptacle connector assembly designed for IEEE 1386 compliant board-to-board applications. This surface mount connector features a 1.0 mm free height design with vertical PCB mounting orientation, supporting stack heights of 8.00 mm, 9.00 mm, or 10.00 mm. The connector utilizes phosphor bronze contacts with gold plating on mating areas (1.27 µm thickness) and tin-lead plating on termination areas, rated for 0.8 A current and 250 VAC/VDC operating voltage. With dimensions of 34.22 mm (L) × 6.04 mm (W) × 5.37 mm (H) and an operating temperature range of -55°C to +110°C, it supports differential signaling and is reflow solder capable up to 260°C. This connector is ideal for high-density board-to-board signal transmission in applications requiring reliable mezzanine interconnections.