Littelfuse SMART FUSE MAXI 40A 1PK (30-1040) MAXI Fuse provides excellent time delay characteristics and low heat dissipation. Designed and patented by Littelfuse, the MAXI Fuse is ideal for motor powered applications which have large inrush currents. Smart Glow fuses are innovative automotive style fuses (ATO, Mini, Maxi and glass tube) that feature an indicator light that glows when the fuse is blown, saving time to troubleshoot an open circuit.