BK/MDA-12-R is a time-delay ceramic tube fuse designed for circuit protection in electrical systems. It features a 1/4" x 1-1/4" (6.35 x 31.75 mm) physical size with ceramic tube construction and nickel-plated brass endcaps, meeting UL standard 248-14. The fuse is rated for 250V AC with a 12-ampere current rating and provides time-delay protection characteristics: no opening at 100% rated current, maximum 60 minutes opening time at 135% current, and maximum 120 seconds opening time at 200% current. It is UL Listed and CSA certified, with optional axial leads available, making it suitable for industrial control circuits, power distribution systems, and equipment requiring reliable overcurrent protection with thermal time-delay characteristics.