Fuse, 200 A, 600V AC, Not Rated, Class J, JLS Series, Nonindicating, Fast Acting, Body Style Blade, Nonrejection, Interrupt Rating 200kA at 600V AC, Fuse Size 3 in L x 5-3/4 in dia, Length 3 in, Width Not Applicable, Depth Not Applicable, Diameter 5 3/4 in, Equivalent Brand and Series Bussmann JKS, Littelfuse JLS, Mersen A4J, Equivalent Series A4J, JKS, JLS, Compatible Fuse Block Series LFJ, Body Material Melamine, Single Element Fast-acting, nonindicating UL Class J fuses open within seconds of being exposed to overloads and short circuits. Also called fast-blow Class J fuses, they are highly sensitive to changes in current flow and don't tolerate temporary overload currents or power surges. They have no indicator for identifying a blown fuse, so they're sometimes used with an indicating.