USI 1206 Surface-Mount Fuses Schurter USI 1206 Surface-Mount Fuses are Quick-Acting F fuses with 32VAC or 63VDC maximum rated voltages. These fuses are IEC 60127-4 rated and offer high melting I2t-values. The USI 1206 fuses are impermeable to the potting compound. These fuses operated at 0.5A to 6.3A rated current range and 63A breaking capacity. Schurter USI 1206 Surface-Mount Fuses are suitable for secondary protection DC and AC and circuits with inrush.