Protector Phospeher Bronze Sleeve Fiber Optic Standard SC/FC/ST Fiber Optic Copper Sleeve Product Description Optical fiber ceramic core is the core component of optical fiber connectors, a special ceramic part with high precision made through processing of ZrO2 and other materials. Widely used in the optical fiber communication industry. Features Highly durable and stable material property under severe environmental conditions Few void/porosity for stable/reliable polishing