The JBX05129 0.5m 400GBASE-CR8 QSFP-DD Direct Attach Copper Cable represents a critical component for modern data center infrastructure. Designed specifically for NVIDIA Mellanox compatibility, this passive DAC cable enables ultra-high-speed data transmission at 400 gigabits per second, supporting the demanding bandwidth requirements of contemporary enterprise environments. **Technical Specifications & Performance:** This cable features premium 30AWG twinax construction with copper connectors at both ends, providing exceptional signal integrity and minimal signal degradation. The 0.5-meter length makes it ideal for short-reach connections between adjacent equipment in dense data center racks. Qualified to ETC 400GBASE-CR8 specifications and QSFP-DD MSA standards, it guarantees compatibility and performance across certified platforms. **Key Features & Benefits:** As a passive DAC solution, this cable requires no external power, reducing complexity and operational costs compared to active alternatives. The direct attach design eliminates transceivers, lowering total cost of ownership while maintaining exceptional reliability. QSFP-DD connectors provide the latest high-density interconnect standard, maximizing port density in constrained rack environments. Operating temperature range of 0-70°C ensures stable performance in various data center climates. **Compliance & Certifications:** Full RoHS and ELV directive compliance (EU directive 2002/95/EC) ensures environmental responsibility. TUV and UL safety certifications validate reliability and safety standards. The cable meets all relevant international standards for data center applications. **Application & Compatibility:** Perfect for connecting NVIDIA Mellanox-based systems including high-performance computing clusters, AI/ML training environments, and enterprise storage solutions. Replaces OEM part numbers 980-9I35R-00W00A and MCP1660-W00AE30, ensuring seamless integration into existing infrastructure. **Value & Support:** Included 90-day limited warranty provides peace of mind. Custom brand programming available for enterprise deployments. Ships from convenient U.S. locations with free standard shipping on orders exceeding $99.