Note: We no longer install the thermal fuse with the last firmware update, December 2017.
https://seemecnc.dozuki.com/Guide/RAMBo+Control+Firmware/50?lang=en
https://github.com/seemecnc/Firmware
These thermal safety fuses are used on our HE280 Hotend. They are NC and open when the max temp is reached, then opening the circuit.