The JBX42499 40-meter ST/APC to ST/UPC duplex singlemode fiber patch cable represents the gold standard in professional fiber optic connectivity. Engineered for mission-critical applications, this cable combines advanced materials with precise manufacturing to deliver consistent, high-quality signal transmission. **Technical Excellence:** This cable features a 9/125 singlemode core with G.657.A1 glass fiber composition, specifically designed for long-distance, low-loss fiber optic communication. The dual polarity configuration (Type A to B crossover) is the industry-standard for duplex patch cord applications, eliminating confusion and ensuring proper installation. Performance metrics exceed industry standards: insertion loss remains at or below 0.35dB with typical performance around 0.15dB, while return loss specification of ≥20dB ensures signal integrity. Attenuation rates of 0.25 dB/km at 1310nm and 0.35 dB/km at 1550nm provide reliable performance across the telecommunications spectrum. **Construction Quality:** The distinctive yellow OFNR (Optical Fiber Non-conductive Riser Rated) jacket offers both visibility and safety compliance. The 1.8mm outer diameter accommodates standard conduit and cable management systems. All materials meet RoHS and EU directive 2002/95/EC compliance standards, ensuring environmental responsibility and regulatory compliance across global markets. **Versatile Applications:** Ideal for data center interconnects, telecommunications networks, campus area networks, and any installation requiring duplex singlemode fiber connectivity. The 40-meter length provides flexibility for medium to long-distance runs while maintaining performance. **Value & Availability:** TAA compliant for government and GSA contract requirements. Custom lengths available for specialized installations. Ships from multiple US locations (Danville CA, Fort Worth TX, Beaufort SC) with free standard shipping on orders exceeding $99. Backed by a 90-day limited warranty, this cable represents a reliable investment in your network infrastructure. Whether upgrading existing systems or building new fiber optic networks, the JBX42499 delivers professional-grade performance where reliability matters.