Metal Cap & Chain for FC Mating Sleeve/FC Adapter provides reliable dust protection for unused FC ports in fiber optic systems. Constructed from durable metal, the cap securely attaches to the adapter and includes a built-in chain to prevent loss during operation or maintenance. Ideal for both FC mating sleeves and FC adapters, this cap ensures long-term port cleanliness and mechanical safety in various fiber optic environments. Perfect for lab, telecom, and field applications.