BK/MDL-2-1/2-R is a time-delay glass tube fuse designed for circuit protection in electrical systems. It features a 1/4 x 1 1/4 inch (6.4 x 31.7 mm) physical size with nickel-plated brass endcaps and is constructed from glass tubing to provide reliable performance. The fuse is rated at 250 Vac with an AC interrupting rating of 100 A at 250 Vac and 10,000 A at 125 Vac, offering a typical DC cold resistance of 0.156 O and a typical melting I²t of 22.7 A²·s. It meets UL standard 248-14 and is RoHS compliant (2002/95/EC), with optional axial leads and board-washable configurations available. This fuse is commonly used in industrial control circuits, power distribution systems, and electronic equipment where time-delay protection and precise current interruption are required.