Komatsulite™ NR-C Mini-Breakers Bourns Komatsulite™ NR-C Mini-Breakers (Thermal Cutoff Devices) are designed to help prevent heat and fires caused by excess current. The NR-C series are self-preserving devices designed to stay tripped (operated) during abnormal temperatures and then recover when power is cut and the temperature returns to a safe level. Bourns Komatsulite NR-C Mini-Breakers are RoHS compliant and halogen-free and offer battery cell protection for notebook and tablet PCs as well as mobile phones.