BK/FBI is a fuse holder cap designed for use with standard fuse holders, featuring a spring-loaded bayonet-type mechanism with tin-plated brass construction and a screwdriver-slotted knob. The component is manufactured from high dielectric molded phenolic material with a UL 94V0 flammability rating, providing excellent electrical insulation and safety characteristics. It offers electrical ratings of 16A @ 250V (UL), 12A @ 250V (CSA), 6.3A @ 250V (VDE), and 10A @ 250V (SEMKO), with insulation resistance of 10 megohm at 500Vdc and contact resistance less than 0.005 ohms. The fuse holder cap operates reliably across a temperature range with body rated to 150°C and knob rated to 130°C, making it suitable for industrial control panels, power distribution equipment, and general electrical protection applications where reliable fuse access and replacement are required.