SR-5 Micro Fuses Bussmann / Eaton SR-5 Micro Fuses provide a compact option for primary circuit protection. The round SR-5 micro-fuses offer equivalent product performance to typical 5mm glass fuses with a 60% footprint reduction. The thru-hole mounted SR-5 micro-fuses are a cost-effective alternative to traditional electronic ferrule fuses. Bussmann / Eaton SR-5 Micro Fuses carry a diverse offering of fast-acting and time-delay options in both IEC and UL designs.