The JBX05021 0.5m 400GBASE-CR8 QSFP-DD to 4x QSFP28 direct attach copper cable represents the pinnacle of cost-effective, high-performance data center interconnectivity. Engineered as a drop-in replacement for Arista's CAB-D-4Q-200G-0.5M, this breakout cable seamlessly integrates into existing network architectures while delivering superior reliability and performance. **Key Technical Features:** This passive breakout DAC employs premium 30AWG twinax copper conductors encased in protective plastic jacketing, ensuring durability without compromising flexibility. The single QSFP-DD interface transitions to four independent QSFP28 connections, enabling 1:4 port expansion while maintaining full 400GB throughput capacity across the breakout lanes. **Performance & Compliance:** Qualified to ETC 400GBASE-CR8 specifications, this cable supports transmission of low-voltage network signals with exceptional signal fidelity over the 0.5-meter span. It carries full RoHS/ELV compliance certification, TUV and UL safety approvals, and adheres to EU Directive 2002/95/EC standards—essential for regulated environments and green IT initiatives. **Ideal Applications:** Perfect for high-density data centers requiring flexible port aggregation, cloud infrastructure deployments, storage area networks (SANs), and enterprise backbone connectivity. The compact 12x12x2 inch form factor optimizes cabinet space utilization while the 0.5-meter length accommodates both top-of-rack and end-of-row switch configurations. **Reliability & Support:** Backed by a comprehensive 90-day limited warranty, this cable undergoes rigorous quality testing to ensure consistent performance. Custom brand programming is available for enterprise customers requiring proprietary identification. Ships from strategically located U.S. warehouses with free standard shipping on qualifying orders. **Operating Specifications:** Temperature range: 0 to 70°C (32 to 158°F), ensuring reliable operation across diverse data center environments. Manufactured in Vietnam and China using ISO-certified processes, this cable delivers enterprise-grade quality at professional pricing.