Plug Fuse, 20A, 125V AC, Not Rated, S Series, Indicating, Time Delay, Body Style Screw-In, Rejection, Interrupt Rating 10kA at 125V AC, Equivalent Brand and Series Bussmann S, Littelfuse S, Littelfuse SLO, Littelfuse SOO, Mersen S, Equivalent Series S, SLO, SOO, Body Material Ceramic, Dual Element, Standards CE, UL 248-11 Guide JFHR, CSA Class 1423-01, Package Quantity 4 Time-delay plug fuses are medium- to heavy-duty fuses for protecting residential or industrial electrical circuits with motors, relays, or solenoids. These slow-blow plug fuses tolerate temporary inrush currents without opening. Series SL fuses are medium-duty fuses for residential circuits. Series S and T fuses provide heavy-duty protection for industrial motors or critical residential circuits.