FC-SQ Adapter with square flange, metal housing with square mounting flange Square flange provides stable installation and precise positioning; high-strength, corrosion-resistant metal housing fits standard ODF/patch panel mountingFC-SQ Adapter with square flange, metal housing with square mounting flange Square flange provides stable installation and precise positioning; high-strength, corrosion-resistant metal housing fits standard ODF/patch panel mountingFibertronics, Inc. FC Fiber Optic Adapters and Couplers are high performing. This standard footprint adapter with full flange or no flange offers a quick and easy solution to extend an. FC bare fiber adapter is used as the tester tool to temporarily connect the bare fiber with fiber optic equipment without having to attach a permanent connector. It provides a simple and effective way to use un-terminated fibers with standard FC receptacles.