FLA Series Indicating Type Slo-Blo Midget Fuse. FLA fuses are 125 volt, pin-indicating time-delay fuses for protection of control circuit transformers, solenoids, and other circuits with high inrush currents. Metal indicating pin pops-out when fuse opens. Pin gives visual indication of open fuse. Use FLA fuses in conjunction with special fuseblocks to operate mechanical signal switches or energize alarm circuits. Fuses rated 12 amperes and above have dual-tube construction.